Motion detection

ABSTRACT

A motion sensor has at least two tiers of monitored volumes that are offset from each other. Electromagnetic radiation, such as infrared light, is directed from the monitored volumes onto at least two sets of detector elements having separate outputs on a pyroelectric substrate of an infrared detector. As a warm object, such as a human or an animal, moves through the monitored volumes, the warmth from the object causes the voltage on the outputs of the infrared detector to change. The resultant waveforms are compared and if the two waveforms have a phase relationship corresponding to a critical phase angle that is based on the pitch of the monitored volumes and the offset between the tiers of monitored volumes, an animal-immune motion indication is generated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of international patent applicationPCT/US2013/073799 filed on Dec. 9, 2013, which is hereby incorporated byreference herein in its entirety for any and all purposes.

BACKGROUND

1. Technical Field

The present subject matter relates to motion detection. Morespecifically it relates to multi-output infrared radiation detectors andmotion sensors using such an infrared detector.

2. Description of Related Art

Motion Sensors utilizing infrared (IR) radiation detectors are wellknown. Such sensors are often used in security systems or lightingsystems to detect movement in a monitored space. An infrared detectordetects changes in mid-infrared (IR) radiation having a wavelength ofabout 6-14 microns. These changes are due to temperature differencesbetween a warm object, such as a warm blooded animal, and its backgroundenvironment as the warm object moves through that environment. Upondetection of motion, motion sensors typically activate an audible alarmsuch as a siren, turn on a light, and/or transmit an indication thatmotion has been detected.

A typical infrared detector utilizes a pyroelectric or piezoelectricsubstrate with a detector element that consists of conductive areas onopposite sides of the substrate, acting as a capacitor. As the substratechanges temperature, charge is added or subtracted to the capacitor,changing the voltage across the capacitor. The amount of mid-IRradiation that hits the detector element determines the temperature ofthat area of the substrate, and therefore, the voltage across thecapacitor that makes up the detector element. Some motion sensorsutilize an infrared detector that includes multiple detector elements.To reduce the chance of false alarms, some infrared detectors include apair of equally sized detector elements of opposing polarities.Non-focused out-of-band radiation, as well as ambient temperaturechanges or physical shock, is equally incident on both detectorelements, thus causing the signals from the equal and opposite elementsto roughly cancel one another.

Many motion sensors incorporate an optical array (comprised of opticalelements, such as lenses, focusing mirrors, and so on) to be able tomonitor a large space with a single infrared detector. The optical arraydirects the IR radiation from multiple monitored volumes onto theinfrared detector, which sometimes includes filters to minimize theradiation outside of the desired mid-infrared range from reaching theinfrared detector. Each of the monitored volumes is typically apyramidal shaped volume extending into the space to be monitored withthe apex of the pyramid at the motion sensor. Concentrations ofradiation from each of the pyramids are projected by the optical arrayson to the infrared detector where they are superimposed, and differentregions of the infrared detector are heated based on the amount of IRradiation received from the superimposed images. The detector elementson the infrared detector react to the localized heating by changingtheir voltage. The resultant change in voltage across the detectorelements is monitored and used to detect motion in the space beingmonitored.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute partof the specification, illustrate various embodiments of the invention.Together with the general description, the drawings serve to explain theprinciples of the invention. They should not, however, be taken to limitthe invention to the specific embodiment(s) described, but are forexplanation and understanding only. In the drawings:

FIGS. 1A and 1B are a front and rear view of an embodiment of aninfrared detector;

FIG. 1C is a schematic of the embodiment of the infrared detector ofFIG. 1A/B;

FIG. 1D is an isometric view of an embodiment of a packaged version ofthe infrared detector of FIG. 1A/B;

FIGS. 2A and 2B are example waveforms from the embodiment of theinfrared detector of FIG. 1;

FIG. 3 shows alternate embodiments of an infrared detector;

FIGS. 4A and 4B are a front and rear view of another embodiment of aninfrared detector;

FIG. 4C is a schematic of the embodiment of the motion detector of FIG.4A/B;

FIG. 4D is an isometric view of an embodiment of a packaged version ofthe infrared detector of FIG. 4A/B;

FIG. 5A-D show embodiments of circuitry for use with an infrareddetector;

FIGS. 6A and 6B show examples of a person and an animal, respectively,walking through monitored volumes of an embodiment of a motion sensor;

FIGS. 7A and 7B are example waveforms from an embodiment of an infrareddetector in the motion sensor of FIGS. 6A and 6B, respectively;

FIG. 8 shows a side view and a top view of an embodiment of monitoredvolumes for a motion sensor in a room;

FIG. 9A-C show embodiments of optical systems for use in a motionsensor;

FIG. 10 shows a block diagram of an embodiment of a motion sensor; and

FIG. 11 shows a flow chart of an embodiment of a method to detectmotion.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant teachings. However, it should be apparent to those skilledin the art that the present teachings may be practiced without suchdetails. In other instances, well known methods, procedures andcomponents have been described at a relatively high-level, withoutdetail, in order to avoid unnecessarily obscuring aspects of the presentconcepts. A number of descriptive terms and phrases are used indescribing the various embodiments of this disclosure. These descriptiveterms and phrases are used to convey a generally agreed upon meaning tothose skilled in the art unless a different definition is given in thisspecification. Some descriptive terms and phrases that may be givenmeanings differently than their generally accepted definitions arepresented in the following paragraphs for clarity.

A pyroelectric material is a material that temporarily generates avoltage as it is heated or cooled. If the temperature remains constant,the voltage may gradually disappear due to leakage current, depending onthe pyroelectric material used. Examples of pyroelectric materialsinclude the mineral tourmaline and the compounds gallium nitride, cesiumnitrate, cobalt phthalocyanine, and lithium tantalite. A piezoelectricmaterial is a material that generates a voltage in response tomechanical stress. Examples of piezoelectric materials includetourmaline, quartz, topaz, cane sugar, and sodium potassium tartratetetrahydrate. Some materials exhibit both pyroelectric and piezoelectricproperties and localized heating of a piezoelectric material can causemechanical stress which then generates a voltage. Therefore, while thedetailed physical properties of pyroelectric materials and piezoelectricmaterials are different, the two terms are used as synonyms herein andin the claims. Thus, a reference to a pyroelectric material includesboth pyroelectric materials and piezoelectric materials.

An infrared radiation detector, or simply infrared detector or IRdetector, is a component having one or more outputs to provideinformation related to warm objects in a field of view of the infrareddetector. An infrared detector has one or more detector elements on apyroelectric substrate. The detector elements receive electromagneticradiation, such as mid-infrared radiation, and receive a pyroelectriccharge from the substrate which is then exhibited at the outputs of theinfrared detector.

A motion sensor is a system for detecting motion in a monitored space. Amotion sensor includes one or more infrared detectors, an optical systemto direct electromagnetic radiation from the monitored space onto theinfrared detector(s), and circuitry to receive the information relatedto motion from the infrared detector(s) and take action based on thatinformation. Any type of action can be taken, but various embodimentstake actions such as, but not limited to, sounding an audible alarm,turning a light on or off, or sending a message indicating that motionwas detected.

In at least some embodiments, a motion sensor has at least two tiers ofmonitored volumes that are offset from each other. Electromagneticradiation, such as infrared light, is directed from the monitoredvolumes onto at least two sets of detector elements having separateoutputs on a pyroelectric substrate of an infrared detector. As a warmobject, such as a human or an animal, moves through the monitoredvolumes, the warmth from the object causes the voltage on the outputs ofthe infrared detector to change. The resultant waveforms are comparedand if the two waveforms have a phase relationship corresponding to acritical phase angle that is based on the pitch of the monitored volumesand the offset between the tiers of monitored volumes, an animal-immunemotion, or major motion, indication is generated. An animal-immunemotion, or major motion, indication is generated in response to a largewarm body, such as a human, moving through the monitored volumes.Movement by a small warm body, such as a dog or a cat does not generatean animal-immune motion, or major motion, indication.

The term “corresponding to a critical phase angle,” as used in thisdisclosure including the claims, means that the phase difference, orphase relationship, is close to the critical phase angle, or is within arange that contains the critical phase angle. In some embodiments, thephase relationship may be deemed to correspond to the critical phaseangle if it falls within about ±10° of the critical phase angle. In atleast one embodiment, the phase relationship may be deemed to correspondto the critical phase angle if it falls within about ±30° of thecritical phase angle. In other embodiments, the range that correspondsto the critical phase angle may be of any size and/or may be asymmetricaround the critical phase angle.

Embodiments of a motion sensor built in accordance with the presentdisclosure direct infrared light from a first set of monitored volumesfrom within the monitored space onto a first set of detector elementsand from a second set of monitored volumes from within the monitoredspace onto a second set of detector elements. The first set of monitoredvolumes and the second set of monitored volumes have different azimuthangles from the motion sensor, or are offset from each other, and areinterleaved, so as an object moves through the monitored volumes, anoutput from the first set of detector elements and an output from thesecond set of detector elements are similar but have a phase difference.By detecting a phase difference between the outputs that corresponds tothe azimuth difference (a critical phase angle), false positives arereduced as compared to traditional motion sensors.

In some embodiments, the optical system creates the different azimuthangles for the two sets of monitored volumes, but in other embodiments,the arrangement of the detector elements on the infrared detectorcreates the different azimuth angles. In some embodiments, the phasedifference of the two outputs is an angle other than a multiple of 90degrees (0°, 90°, 180°, 270° and so on).

In some embodiments, the first set of monitored volumes and the secondset of monitored volumes are at different elevations from the motionsensor to allow the two sets of monitored volumes to project todifferent distances from the motion sensor. If the two sets of monitoredvolumes have different elevations, objects that are large enough tointersect both sets of monitored volumes can be differentiated fromobjects that are small enough to intersect only one set of monitoredvolumes. This allows some embodiments to differentiate between majormotion (e.g. that of a walking human, but not that of the ordinarymotion of a small animal, such as a pet) and minor motion (e.g. due tomonitored volumes' occupancy by a seated and slightly-moving human, ordue to the ordinary motion of a small animal, such as a pet).

Reference now is made in detail to the examples illustrated in theaccompanying drawings and discussed below.

FIGS. 1A and 1B are a front and rear view, respectively, of anembodiment of an infrared detector 100. The infrared detector includes asubstrate 101 made with a pyroelectric material. In some embodiments,the substrate 101 is entirely or nearly entirely made from apyroelectric material, but in other embodiments, the substrate 101 ismade from an inert insulator with one or more coatings or layers of apyroelectric material. Other embodiments use different constructions ofthe substrate 101, but still include pyroelectric material in thesubstrate 101.

The infrared detector 100 includes a first set of detector elements thatincludes one detector element 130 that includes pad 113 on the frontside 110 of the substrate 101 and pad 123 on the back side 120 of thesubstrate 101, and another detector element 140 that includes pad 114 onthe front side 110 of the substrate 101 and pad 124 on the back side 120of the substrate 101. Note that pad 123 is nearly directly opposite ofpad 113 on the substrate 101, and pad 124 is nearly directly opposite ofpad 114 on the substrate 101. The two detector elements 130, 140 of thefirst set of detector elements are positioned on the substrate 101spaced a pitch distance 131 apart. In some embodiments, the two detectorelements 130, 140 are approximately the same size, but in otherembodiments, they may have different sizes. The detector element 130 iscoupled between an output pad 122 and the detector element 140, which iscoupled to another output pad 125. Thus, the first set of detectorelements includes at least two serially coupled detector elements 130,140. In the embodiment shown, the detector element 130 is configured toprovide a positive voltage between the output pad 125 and the output pad122 in response to a positive change in temperature, and the detectorelement 140 is configured to provide a negative voltage between theoutput pad 125 and the output pad 122 in response to a positive changein temperature.

The infrared detector 100 also includes a second set of detectorelements that includes one detector element 170 that includes pad 117 onthe front side 110 of the substrate 101 and pad 127 on the back side 120of the substrate 101, and another detector element 180 that includes pad118 on the front side 110 of the substrate 101 and pad 128 on the backside 120 of the substrate 101. Note that pad 127 is nearly directlyopposite of pad 117 on the substrate 101, and pad 128 is nearly directlyopposite of pad 118 on the substrate 101. The two detector elements 170,180 of the second set of detector elements are positioned on thesubstrate 101 spaced a pitch distance 132 apart. In embodiments, thepitch distance 131 of the first set of detector elements isapproximately the same as the pitch distance 132 of the second set ofdetector elements. In embodiments, detector element 170 is approximatelythe same size as detector element 130, and detector element 180 isapproximately the same size as detector element 140. All four detectorelements 130, 140, 170, 180 are approximately the same size in someembodiments. The detector element 170 is coupled between an output pad126 and the detector element 180, which is coupled to another output pad129. Thus, the second set of detector elements includes at least twoserially coupled detector elements 170, 180. In the embodiment shown,the detector element 170 is configured to provide a positive voltagebetween the output pad 129 and the output pad 126 in response to anincrease in temperature, and the detector element 180 is configured toprovide a negative voltage between the output pad 129 and the output pad126 in response to the increase in temperature.

In the embodiment of FIG. 1A/B, the first set of detector elements 130,140 and the second set of detector elements 170, 180 are overlapping andapproximately aligned in one direction, (e.g. vertical in FIG. 1A/B),but are interleaved and positioned with an offset 133 in the orthogonaldirection (e.g. horizontal in FIG. 1A/B). The offset 133 can becharacterized as a percentage of the pitch distance 131, 132. If theoffset 133 is half (50%) of the pitch distance 131, 132, the offset 133can be referred to as a quadrature offset, because the pitch distance131, 132 represents one half of a full cycle of a waveform where thefirst detector element of a set of detector elements (e.g. detectorelement 130) represents the beginning of the cycle, and the seconddetector element of the set of detector elements (e.g. detector element140) represents the beginning of the second half of the cycle due to itsopposite polarity. If the offset 133 is not equal to one half of thepitch distance 131, 132, the offset 133 can be referred to as anon-quadrature offset. A non-quadrature offset is a physical offset withrespect to a common axis that is not a multiple of one half of the pitchdistance and is non-zero. In the embodiment shown in FIG. 1A/B, thesecond set of detector elements 170, 180 are positioned with anon-quadrature offset 133 from the first set of detector elements 130,140. In some embodiments, the non-quadrature offset 133 is between about5% of the pitch distance 131, 132 and about 45% of the pitch distance131, 132 or between about 55% of the pitch distance 131, 132 and about95% of the pitch distance 131, 132. In at least one embodiment, thenon-quadrature offset 133 is about one third or about two thirds of thepitch distance 131, 132.

FIG. 1C is a schematic of the embodiment of the infrared detector 100 ofFIG. 1A/B. The first set of serially coupled detector elements 112 areshown as polarized capacitors 130, 140 to indicate the polarity ofvoltage generated by the detector element in response to an increase intemperature. The electrodes of the capacitors 130, 140 are marked withthe reference number of its corresponding pad of the detector element.So the detector element, or capacitor, 130 includes pad 123 and pad 113,and detector element, or capacitor, 140 includes pad 114, and pad 124.The first set of detector elements 112 is coupled to the output pad 122and to the output pad 125.

The second set of serially coupled detector elements 116 are shown aspolarized capacitors 170, 180 to indicate the polarity of voltagegenerated by the detector element in response to an increase intemperature. The electrodes of the capacitors 170, 180 are marked withthe reference number of its corresponding pad of the detector element.So the detector element, or capacitor, 170 includes pad 127 and pad 117,and detector element, or capacitor, 180 includes pad 118, and pad 128.The second set of detector elements 116 is coupled to the output pad 126and to the output pad 129. In at least some embodiments, the output pad125 and output pad 129 are coupled to ground, the output pad 122 is afirst output of the infrared detector 100, and the output pad 126 is thesecond output of the infrared detector 100. So in at least someembodiments, a first output 122 is coupled to the first set of detectorelements 112, and a second output 126 is coupled to the second set ofdetector elements 116.

FIG. 1D is an isometric view of an embodiment of a packaged version 190of the infrared detector 100 of FIG. 1A/B. The packaged version 190includes a package 191, such as a standard TO-5 metal housing or someother type of packaging, with the substrate 101 of the infrared detector100 mounted inside of the package 191 behind a mid-IR-transmissivewindow (or window/filter) in a way to allow external mid-IRelectromagnetic energy to affect the substrate 101 of the infrareddetector 100 while at the same time shielding the substrate 101 fromnon-mid-IR influences. The packaged version 190 includes at least oneterminal 192-199 accessible from outside of the package. The packagedversion 190 includes circuitry, mounted in the package 191 and coupledbetween the detector elements of the infrared detector 100 and the atleast one output terminal 192-199. In some embodiments, the circuitrysimply provides electrical connectivity between the substrate 101 andthe at least one terminal 192-199. In at least one embodiment, theoutput terminal 192 is coupled to the output pad 122, the outputterminal 195 is coupled to the output pad 125, the output terminal 196is coupled to the output pad 126, and the output terminal 199 is coupledto the output pad 129. In other embodiments, the circuitry can detect afirst pyroelectric effect on the first set of detector elements 112 anda second pyroelectric effect on the second set of detector elements 116,and provide information about the first pyroelectric effect and thesecond pyroelectric effect at the at least one output terminal 192-199.In at least one embodiment, the output terminal 195 is a power input forthe circuitry which includes transistor buffers, the output terminal 199is a ground terminal and is coupled to the output pad 125 and the outputpad 129, the output pad 122 is coupled through a transistor buffer tooutput terminal 192, and the output pad 126 is coupled through atransistor buffer to output terminal 196. In yet another embodiment, theoutput terminal 195 is a power input for the circuitry which includestwo analog to digital converters (ADC), the output terminal 199 is aground terminal and is coupled to the output pad 125 and the output pad129, the output pad 122 is coupled to a first ADC, whose output iscoupled to the output terminal 192, and the output pad 126 is coupled toa second ADC, whose output is coupled to the output terminal 196. Inanother embodiment, the output terminal 195 is a power input for thecircuitry which includes an analog to digital converter (ADC), theoutput terminal 199 is a ground terminal and is coupled to the outputpad 125 and the output pad 129, and the output pad 122 and the outputpad 126 are both coupled to the ADC, whose output is coupled to theoutput terminal 192, and output terminal 196 is omitted from theembodiment or is not coupled to the circuitry or the infrared detector100.

FIGS. 2A and 2B are example waveforms from the embodiment of theinfrared detector 100 of FIG. 1A/B. FIG. 2A shows waveforms 200representing the response of the infrared detector 100 to infrared lightfrom a warm object moving across the monitored space directed onto theinfrared detector 100. It should be noted that the waveforms 210 may notrepresent any particular moving object or actual monitored spaceenvironment, but are provided here to help explain the operation of theinfrared detector 100. The waveforms 200 include waveform 201representing the voltage across the first set of detector elements 112,or the voltage at the output pad 122, assuming that the output pad 125is grounded. The waveforms 200 also include waveform 205 representingthe voltage across the second set of detector elements 116, or thevoltage at the output pad 126, assuming that the output pad 129 isgrounded.

In response to infrared light from the warm object moving through amonitored volume directed onto the first detector element 130, thedetector element 130 generates a positive voltage 202 for waveform 201.As the warm object moves from the monitored volume from which infraredradiation is directed onto the detector element 130, to the monitoredvolume from which infrared radiation is directed onto the detectorelement 170, the voltage on the waveform 201 begins to drop, and thedetector element 170 generates a positive voltage 206 for waveform 205.As the warm object moves from the monitored volume from which infraredradiation is directed onto the detector element 170, to the monitoredvolume from which infrared radiation is directed onto the detectorelement 140, the voltage on the waveform 205 begins to drop, and thedetector element 140 generates a negative voltage 203 for waveform 201.Then, as the warm object moves from the monitored volume from whichinfrared radiation is directed onto the detector element 140, to themonitored volume from which infrared radiation is directed onto thedetector element 180, the voltage on the waveform 201 begins to rise,and the detector element 180 generates a negative voltage 207 forwaveform 205. The time 204 from the maximum voltage 202 to the minimumvoltage 203 of the waveform 201 can be thought of as half of one fullcycle, or period, of the waveform 201. The time 208 from the maximumvoltage 206 to the minimum voltage 207 of the waveform 205 can bethought of as half of one full cycle, or period, of the waveform 205.

The motion of the warm object generates a first waveform 201 across thefirst set of detector elements 112, and a second waveform 205 across thesecond set of detector elements 116. Because the first set of detectorelements 112 and the second set of detector elements 116 haveapproximately the same size and pitch, the first waveform 201 and thesecond waveform 202 are approximately equivalent and have about the samehalf period 204, 208. But because the first set of detector elements 112and the second set of detector elements 116 have an offset 133, there isphase shift between the two waveforms 201, 205 shown by the phase delay209. The phase shift, or phase angle difference, can be calculated bycomparing the phase delay 209 to the half period 204, 208. The phaseshift can be calculated as a percentage of the half period 204, 208,which corresponds to the offset between the first set of detectorelements 112 and the second set of detector elements 116, although otherembodiments may calculate the phase shift as an angle by multiplying thecalculated percentage by 180°. If the calculated phase shift correspondsto the offset 133 between the two sets of detector elements 112, 116,the waveforms 201, 205 were very likely to have been caused by actualmovement of a warm object through the monitored space. If a phase shiftis found between the two waveforms 201, 205 that does not correspond tothe offset between the two sets of detector elements 112, 116, thewaveforms 201, 205 were likely not caused by actual movement, but bysome other cause. This behavior can be used to reduce the generation offalse detections of movement, or false alarms.

The term “corresponding to the offset,” as used in this disclosureincluding the claims, means that the phase difference, or phaserelationship, of the detected waveforms, as a percentage of a half cycle(180°), is close the offset calculated as a percentage of the pitch ofthe detector elements, or is within a range that contains the offset. Insome embodiments, the phase relationship may be deemed to correspond tothe critical phase angle if it falls within a range about the offset ofabout ±6% of the pitch (e.g. a range of about 27% to about 39% if theoffset is 33%). In at least one embodiment, the phase relationship maybe deemed to correspond to the critical phase angle if it falls within arange about the offset of about ±20% of the pitch (e.g. a range of about13% to about 53% if the offset is 33%). In other embodiments, the rangethat corresponds to the offset may be of any size, and/or may beasymmetric around the offset.

FIG. 2B shows waveforms 210 representing the response of the infrareddetector 100 to a sudden change in temperature of the infrared detector100 or some sort of mechanical shock received by the infrared detector100 that might cause a false detection of movement in prior systems. Itshould be noted that the waveforms 210 may not represent an actualevent, but are provided here to help explain the operation of theinfrared detector 100. The waveforms 210 include waveform 211representing the voltage across the first set of detector elements 112,or the voltage at the output pad 122 assuming that the output pad 125 isgrounded. The waveforms 210 also include waveform 215 representing thevoltage across the first set of detector elements 116, or the voltage atthe output pad 126 assuming that the output pad 129 is grounded. Notethat the first waveform 211 and the second waveform rise together to amaximum 212 and a maximum 216, respectively, and then fall together to aminimum 213 and a minimum 217, respectively. Both waveforms 211, 215have a half period 214 that is equal but there is no phase shift betweenthe two waveforms 211, 215. As such, it can be determined that thewaveforms 210 are not indicative of movement, and no indication ofmovement would be generated by embodiments of a motion sensor inresponse to these waveforms.

FIG. 3 shows alternate embodiments of an infrared (IR) detector. Theembodiments shown all include a pyroelectric substrate with a pluralityof detector elements. A first alternate embodiment of an infrareddetector 300 includes a first set of two serially coupled detectorelements 301 and a second set of two serially coupled detector elements302. The first set of serially coupled detector elements 301 comprises afirst row, and the second set of detector elements 302 comprises asecond row that is non-overlapping with the first row. The first set ofdetector elements 301 has a non-quadrature offset from the second set ofdetector elements 302 in the infrared detector 300, but the detectorelements are sized so that the individual detector elements of the firstset of detector elements 301 overlap with the individual detectorelements of the second set of detector elements 302. Thus, a verticalline through the infrared detector 300 may intersect a detector elementof the first row 301 and a detector element of the second row 302.

A second alternate embodiment of an infrared detector 310 includes afirst set of serially coupled detector elements 311 and a second set ofserially coupled detector elements 312. The first set of seriallycoupled detector elements 311 comprises a first row, and the second setof detector elements 312 comprises a second row that is non-overlappingwith the first row. The first set of detector elements 311 has aquadrature offset from the second set of detector elements 312 in theinfrared detector 310, and the detector elements are sized so that theindividual detector elements of the first set of detector elements 311do not overlap with the individual detector elements of the second setof detector elements 312, but leave little uncovered horizontal spacebetween the two sets of detector elements 311, 312, so that no verticalline through the infrared detector 310 can intersect more than onedetector element, and very few possible vertical lines through theinfrared detector 310 will not intersect any detector elements.

A third alternate embodiment of an infrared detector 320 includes afirst set of serially coupled detector elements 321 and a second set ofserially coupled detector elements 322. The first set of seriallycoupled detector elements 321 comprises a first row, and the second setof detector elements 322 comprises a second row that partially overlapswith the first row. The first set of detector elements 321 has anon-quadrature offset from the second set of detector elements 322 inthe infrared detector 320, and the detector elements are sized so thatthe individual detector elements of the first set of detector elements321 do not horizontally overlap with the individual detector elements ofthe second set of detector elements 322, and leave uncovered horizontalspace between the two sets of detector elements 321, 322 so that novertical line through the infrared detector 320 can intersect more thanone detector element, and some possible vertical lines through theinfrared detector 320 will not intersect any detector elements. The twosets of detector elements 321, 322 do overlap vertically, however, sothat at least one horizontal line may intersect all four detectorelements in this embodiment.

A fourth alternate embodiment of an infrared detector 330 includes afirst set of four serially coupled detector elements 331, a second setof four serially coupled detector elements 332, a third set of fourserially coupled detector elements 333, and a fourth set of seriallycoupled detector elements 334. The four sets of detector elements331-334 are non-overlapping in the vertical direction. The first set ofdetector elements 331 and the third set of detector elements 333 arehorizontally aligned with each other, and the second set of detectorelements 332 and the fourth set of detector elements 334 are alignedwith each other, but have a non-quadrature offset from the first set 330and third set 333.

A wide variety of embodiments are envisioned for various embodiments ofinfrared detectors. Various embodiments can have any number of sets ofdetector elements with any number of detector elements per set. The setscan be overlapping or non-overlapping in a first direction, but at leastsome sets are offset from other sets in a direction orthogonal to thefirst direction. The offset can be a quadrature offset in someembodiments, but is a non-quadrature offset in other embodiments. Thedetector elements can be of any size and the individual detectorelements of a set may or may not overlap with individual detectorelements of adjacent sets in a direction orthogonal to the firstdirection, depending on the embodiment. Each set of detectors can havean individual outputs or can be coupled in parallel with one or moreother sets of detectors, depending on the embodiment. In someembodiments, one end of each set of the serially coupled detectorelements are coupled together to a ground terminal, and the other end ofeach set of the serially coupled detector elements has an individualoutput. In other embodiments, one end of each set of the seriallycoupled detector elements are coupled together to a ground terminal, andthe other end of even rows of the serially coupled detector elements arecoupled to one output, and odd rows of the serially coupled detectorelements are couple to another output.

FIGS. 4A and 4B are a front and rear view of another embodiment of aninfrared detector 400. The infrared detector includes a substrate 401made with at least some pyroelectric material. The infrared detector 400includes a first row of detector elements 412 that includes one detectorelement 430 that includes pad 413 on the front side 410 of the substrate401 and pad 423 on the back side 420 of the substrate 401, and anotherdetector element 440 that includes pad 414 on the front side 410 of thesubstrate 401 and pad 424 on the back side 420 of the substrate 401.Note that pad 423 is opposite of pad 413 on the substrate 401, and pad424 opposite of pad 414 on the substrate 401. The two detector elements430, 440 of the first row of detector elements 412 are positioned on thesubstrate 401 in a row direction (horizontal in FIG. 4A/B) spaced apitch distance 431 apart. In the embodiment shown, the two detectorelements 430, 440 are approximately the same size. The first row ofdetector elements 412 includes at least two serially coupled detectorelements 430, 440 coupled between the output pad 422 and the output pad425. In the embodiment shown, the detector element 430 is configured toprovide a positive voltage between the output pad 425 and the output pad422 in response to an increase in temperature, and the detector element440 is configured to provide a negative voltage between the output pad425 and the output pad 422 in response an increase in temperature.

The infrared detector 400 also includes a second row of detectorelements 416 that includes one detector element 470 that includes pad417 on the front side 410 of the substrate 401 and pad 427 on the backside 420 of the substrate 401, and another detector element 480 thatincludes pad 418 on the front side 410 of the substrate 401 and pad 428on the back side 420 of the substrate 401. Note that pad 427 is oppositeof pad 417 on the substrate 401, and pad 428 is opposite of pad 418 onthe substrate 401. The two detector elements 470, 480 of the second rowof detector elements 418 are positioned on the substrate 401 in a rowdirection that is parallel to the first row 412, and spaced a pitchdistance 432 apart that is about the same as the pitch distance 431 ofthe first row 412. In the embodiment shown, all four detector elements430, 440, 470, 480 are approximately the same size. The second row ofdetector elements 416 includes at least two serially coupled detectorelements 470, 480 coupled between the output pad 426 and the output pad429. In the embodiment shown, the detector element 470 is configured toprovide a positive voltage between the output pad 429 and the output pad426 in response to an increase in temperature, and the detector element480 is configured to provide a negative voltage between the output pad429 and the output pad 426 in response to an increase in temperature.

In the embodiment of FIG. 4A/B, the first row of detector elements 412and the second row of detector elements 416 are substantiallynon-overlapping. Substantially non-overlapping, as used herein and inthe claims, means that more than 80% of the height (i.e. the dimensionorthogonal to the row direction, or vertical in FIG. 4A/B) of detectorelements 430, 440 of the first row 412 do not overlap with the detectorelements 470, 480 of the second row 418. The detector elements 470, 480of the second row 416 are, however, are positioned at a non-zero offset433 from the first row of detector elements 412 in the row direction(horizontal in FIG. 4A/B). The offset 433 can be characterized as apercentage of the pitch distance 431, 432. In some embodiments, thenon-zero offset is between about 5% of the pitch distance and about 95%of the pitch distance. In some embodiments, the offset 433 is about halfof the pitch distance 431, 432 and can be referred to as a quadratureoffset. In some embodiments, the offset 433 is not equal to one half ofthe pitch distance 431, 432, and the offset 433 can be referred to as anon-quadrature offset.

FIG. 4C is a schematic of the embodiment of the infrared detector 400 ofFIG. 4A/B. The first row of serially coupled detector elements 412 areshown as polarized capacitors 430, 440 to indicate the polarity ofvoltage generated by the detector element in response to an increase intemperature. The electrodes of the capacitors 430, 440 are marked withthe reference number of its corresponding pad of the detector element.So the detector element, or capacitor, 430 includes pad 423 and pad 413,and detector element, or capacitor, 440 includes pad 414, and pad 424.The first row of detector elements 412 is coupled to the output pad 422and to the output pad 425.

The second row of serially coupled detector elements 416 are shown aspolarized capacitors 470, 480 to indicate the polarity of voltagegenerated by the detector element in response to an increase intemperature. The electrodes of the capacitors 470, 480 are marked withthe reference number of its corresponding pad of the detector element.So the detector element, or capacitor, 470 includes pad 427 and pad 417,and detector element, or capacitor, 480 includes pad 418, and pad 428.The second row of detector elements 416 is coupled to the output pad 426and to the output pad 429. In at least some embodiments, the output pad425 and output pad 429 are coupled to ground, and the output pad 422 isa first output of the infrared detector 400, and the output pad 426 isthe second output of the infrared detector 400.

FIG. 4D is an isometric view of an embodiment of a packaged version 490of the infrared detector 400 of FIG. 4A/B. The packaged version 490includes a package 491 with the substrate 401 of the infrared detector400 mounted inside of the package 491 behind a mid-IR-transmissivewindow (or window/filter) in a way to allow external mid-IRelectromagnetic energy to affect the substrate 401 of the infrareddetector 400 while at the same time shielding the substrate 101 fromnon-mid-IR influences. The packaged version 490 includes at least oneterminal 492-199 accessible from outside of the package. In at least oneembodiment, the output terminal 492 is coupled to the output pad 422,the output terminal 495 is coupled to the output pad 425, the outputterminal 496 is coupled to the output pad 426, and the output terminal499 is coupled to the output pad 429. Some embodiments of the packagedversion 490 include circuitry, such as shown if FIG. 5A-D, mounted inthe package 491 and coupled between the infrared detector 400 and the atleast one output terminal 492-199.

FIG. 5A-D show embodiments of circuitry for use with an infrareddetector 100 of FIG. 1A-D or an infrared detector 400 of FIG. 4A-D. FIG.5A shows a schematic of an embodiment of a packaged infrared detector500. The packaged infrared detector 500 includes a substrate 509 havingtwo sets of detector elements. The first set of detector elements 501includes a first detector element 502 serially coupled to a seconddetector element 503. The second set of detector elements 505 includes afirst detector element 506 serially coupled to a second detector element507. Circuitry, that in the embodiment shown in FIG. 5A is limited toconductors such as bonding wires, couples one end of both the first setof detector elements 501 and the second set of detector elements 505 toa ground terminal 519. The circuitry also couples the other end of thefirst set of detector elements 501 to a first output 511, and the otherend of the second set of detector elements 505 to a second output 512.

So in the embodiment shown in FIG. 5A, the infrared detector includes afirst set of detector elements 501 and a second set of detector elements505, a first output 511, a second output 512, and a ground terminal. Inthis embodiment, the first set of detector elements 501 consists of afirst detector element 502 and a second detector element 503, and thesecond set of detector elements 505 consists of a third detector element506 and a fourth detector element 507. The first 502, second 503, third506 and fourth detector elements 507 each include a capacitor with thesubstrate 509 as a dielectric. In this embodiment, the first output 511is connected to a first terminal of the first detector element 502, asecond terminal of the first detector element 502 is connected to afirst terminal of the second detector element 503, and a second terminalof the second detector element 503 is connected to the ground terminal519. In this embodiment, the second output 512 is connected to a firstterminal of the third detector element 506, a second terminal of thethird detector element 506 is connected to a first terminal of thefourth detector element 507, and a second terminal of the fourthdetector element 507 is connected to the ground terminal 519.

FIG. 5B shows a schematic of an embodiment of a packaged infrareddetector 520 that includes a substrate 529 having two sets of detectorelements 521, 525. The packaged infrared detector 520 includes circuitry540, mounted in the package 531, and coupled to the package outputs 530,538, 539, the first set of detector elements 521, and second set ofdetector elements 525. The first set of detector elements 521 includes afirst detector element 522 serially coupled to a second detector element523. The second set of detector elements 525 includes a first detectorelement 526 serially coupled to a second detector element 527. One endof both the first set of detector elements 521 and the second set ofdetector elements 525 are coupled to a ground terminal 539. The otherend of the first set of detector elements 521 is coupled to a firstinput 524 of the circuitry 540, and the other end of the second set ofdetector elements 525 is coupled to a second input 528 of the circuitry540. The circuitry 540 is also coupled to the power terminal 538 toprovide power to the circuitry 540, and the ground terminal 539. One ormore outputs of the circuitry 540 are coupled to outputs 530 of thepackaged infrared detector 520. In some embodiments, the circuitry 540can detect a first pyroelectric effect on the first set of detectorelements 521 and a second pyroelectric effect on the second set ofdetector elements 525, and provide information about the firstpyroelectric effect and the second pyroelectric effect at the at leastone output terminal 530. In some embodiments, the information isprovided in the form of one or more analog waveforms. In otherembodiments, the information is provided as digital data. Someembodiments may provide the information as a combination of analog anddigital information.

FIG. 5C shows an embodiment of circuitry 540A suitable for use in thepackaged infrared detector 520 as circuitry 540. The first input 524 iscoupled to a first transistor buffer 541 and the second input 528 iscoupled to a second transistor buffer 542. The first transistor buffer541 and second transistor buffer 542 can be of any design, ranging froma single transistor buffer to a full operational amplifier based design,and can use any type of transistor, including bipolar transistors,depletion-mode field-effect transistors, and enhancement-modefield-effect transistors, as well as other passive or active electroniccomponents such as, but not limited to, diodes, resistors, andcapacitors, depending on the embodiment. In one embodiment, thetransistor buffers 541, 542 have a unity gain, but other embodiments mayprovide non-unity gain to change the voltage range of the output fromthat generated by the pyroelectric effect. The first transistor buffer541 drives output 531, which is one of the at least one output terminal530, with a first analog voltage waveform to provide information aboutthe pyroelectric effect on the first set of detector elements 521. Thesecond transistor buffer 542 drives output 532, which is one of the atleast one output terminal 530, with a second analog voltage waveform toprovide information about the pyroelectric effect on the second set ofdetector elements 525.

FIG. 5D shows an embodiment of circuitry 540B suitable for use in thepackaged infrared detector 520 as circuitry 540. The circuitry 540Bincludes control circuitry 551 with an output 552 coupled to an analogmultiplexer 553 to select one of the two inputs 524, 528 to provide asan input 555 to an analog-to-digital converter (ADC) 557. The ADC 557can have any resolution, depending on the embodiment, but the ADC 557 isa monotonic 14 bit ADC in at least one embodiment. The control circuitry551 also controls the ADC 557 using one or more control lines 556, andthe output 558 of the ADC 557 is made available at the at least oneoutput terminal 530. So in at least one embodiment, the circuitry 540Bincludes at least one analog-to-digital converter 557, and theinformation about the first pyroelectric effect and the secondpyroelectric effect at the at least one output terminal 530 includesdigital data representing at least one voltage waveform.

In some embodiments, the control circuitry 551 includes one or morecontrol lines coupled to external control terminals of the package, withthe output of the ADC 558 directly available on external terminals, butin the embodiment shown, the control circuitry 551 receives the output558 of the ADC 557 and communicates over a bidirectional input/output(I/O) line 535, which is one of the at least one output terminal 530.Any protocol can be used on the I/O line 535, but in one embodiment, acapture and transmission cycle on the I/O line 535 is started by anexternal device by holding the I/O line 535 low for at least a firstpredetermined period of time, then driving it high and releasing it. Thecontrol circuitry 551 detects this and uses the mux control line 552 toselect the first input 524. The control circuitry 551 then uses the ADCcontrol lines 556 to have the ADC 557 convert the voltage of the firstinput 524 to a digital value on the ADC output 558, where it is capturedby the control circuitry 551. Once the digital value of the first input524 has been captured, the control circuitry 551 uses the mux controlline 552 to select the second input 528. The control circuitry 551 thenuses the ADC control lines 556 to have the ADC 557 convert the voltageof the second input 528 to a digital value on the ADC output 558, whereit is captured by the control circuitry 551.

After the I/O line 535 has been driven high and released by the externaldevice, the control circuitry 551 drives one bit of information from thecaptured digital values on the I/O line 535 for a second predeterminedperiod of time and then releases the I/O line 535. The external devicewaits for at least the second predetermined period of time, captures thevalue of the I/O line 535, and then drives the I/O line 535 low and backhigh again. The control circuitry 551 detects the low to high transitionand repeats the process for the next bit of information. This continuesuntil all the digital information from the ADC output 558 has beentransferred. Other embodiments use different protocols to transfer thedigital information on one or more lines. Some embodiments may includemultiple ADCs and multiple outputs to allow for faster and/or simpleraccess to the digital information.

FIGS. 6A and 6B show examples of a person 601 and an animal 602,respectively, walking through a monitored space 600 of an embodiment.The monitored space 600 includes several monitored volumes whosecross-sections, where the person 601 or animal 602 is passing through,are shown as rectangles, although other embodiments can have othershapes for the monitored volumes. A first monitored volume 611 and asecond monitored volume 612 are included in a first row of monitoredvolumes 610, and a third monitored volume 621 and fourth monitoredvolume 622 are included in a second row of monitored volumes 620. In theembodiment shown, the first row of monitored volumes 610 and the secondrow of monitored volumes 620 are substantially non-overlapping. Otherembodiments have more than two rows of monitored volumes at for at leastsome intersecting planes of the monitored space 600.

The first row of monitored volumes 610 in the monitored space 600 have apitch 631, or distance between the monitored volumes 611, 612, that isabout the same as the pitch of the second row of monitored volumes 620.The second row of monitored volumes 620, however, has a non-zero offset633 from the first row of monitored volumes 610 in the monitored space600. The offset 633 is in the same direction of the flow of the rows, orhorizontal in FIG. 6A/B. One way of measuring the offset 633 is to findthe distance from the left edge of the first monitored volume 611 to theleft edge of the third monitored volume 621. The offset 633 can also becalculated as a percentage of the pitch 631, or as a phase angle, wherethe phase angle is equal to:

φ=180°×Offset/Pitch

In various embodiments, the non-zero offset 633 can any non-zero value,but in most embodiments, the non-zero offset 633 will be no greater thanthe pitch. So in many embodiments, the offset is limited to:

0°<φ<180°

In some embodiments, the phase angle is about 90°, so that the thermalinformation from the first row 610 and the thermal information from thesecond row 620 are quadrature signals, but in other embodiments, thephase angle is not close to 0°, 90°, or 180°, so that:

10°≦φ≦80°∪100°≦φ≦170°

In FIG. 6A, the person 601 is passing through the monitored space 600from left to right. As the person 601 moves, she first moves into thefirst monitored volume 611 of the first row of monitored volumes 610.Thermal information from the person 601 is directed onto a detectorelement of an infrared detector in a motion sensor that is monitoringthe first monitored volume 611. As the person 601 continues to move,thermal information from the person 601 is directed onto the variousdetector elements of the infrared detector in the motion sensor. As theperson 601 moves out of the first monitored volume 611, she moves intothe third monitored volume 621, then into the second monitored volume612 and finally into the fourth monitored volume 622. In at least someembodiments, the thermal information from the first row of monitoredvolumes 610 is based on a positive contribution to the thermalinformation by a hot object in the first monitored volume 611 and anegative contribution to the thermal information by a hot object in thesecond monitored volume 612, and the thermal information from the secondrow of monitored volumes 620 is based on a positive contribution to thethermal information by a hot object in the third monitored volume 621and a negative contribution to the thermal information by a hot objectin the fourth monitored volume 622.

In some embodiments, the motion sensor includes circuitry coupled to theinfrared detector to detect a phase relationship of waveforms extractedfrom the thermal information from the first row of monitored volumes 610and the thermal information from the second row of monitored volumes620. The circuitry in the motion sensor can then generate ananimal-immune (major motion) indication if the phase relationshipcorresponds to a critical phase angle, where the critical phase angle isgreater than 0 degrees and is based on the offset 633 and the pitch 631.

I should be noted that, for many different reasons, a phaserelationship, or phase delay, (φ′) can correspond to a critical phaseangle (φ) without being exactly equal. To allow for motion in variousdirections, as well as variations in the way that the angles arecalculated, some embodiments use the absolute value of the phase delay(|φ′|) to determine if the phase delay corresponds to the critical phaseangle. Some embodiments also normalize the angles so that both the phasedelay and the critical phase angles are between 0° and 180° for thedetermination of correspondence. Some embodiments also determine thatthe phase angle corresponds to the critical phase angle if:

180°−|φ′|≈φ

In some embodiments, a predetermined tolerance factor is used so that ifthe phase delay differs from the critical phase angle by less than thetolerance factor, the two are deemed to be corresponding. The tolerancefactor allows for some variation in the speed or path of the movingobject to be tolerated and still generate a valid detection of motion.The predetermined tolerance factor varies in different embodiments, butis ±10° in at least one embodiment and ±6% of the pitch in anotherembodiment. In some embodiments, the tolerance factor varies, dependingon the magnitude of the waveforms or a correlation factor between thetwo waveforms.

In FIG. 6B, the animal 602 is passing through the monitored space 600from left to right. As the animal 602 moves, it first moves into thethird monitored volume 621 of the second row of monitored volumes 620without entering the first monitored volume 611 of the first row ofmonitored volumes 610 because it is not tall enough to enter the firstrow of monitored volumes 610. Thermal information from the animal 602 isdirected onto a detector element of an infrared detector in a motionsensor that is monitoring the third monitored volume 621. As the animal602 continues to move, thermal information from the animal 602 isdirected onto the various detector elements of the infrared detector inthe motion sensor. As the animal 602 moves out of the third monitoredvolume 621, it moves into the fourth monitored volume 622 withoutentering into the second monitored volume 612. So thermal informationfrom the animal 602 is available from the second row of monitoredvolumes 620, but because the animal 602 is not tall enough to reach thefirst row of monitored volumes 610 of the monitored space 600, nothermal information from the animal 602 is available from the first rowof monitored volumes 610. This allows embodiments to differentiatebetween a human 601 and an animal 602 moving through the monitored space600.

FIGS. 7A and 7B show example waveforms from an embodiment of an infrareddetector in the motion sensor of FIGS. 6A and 6B. FIG. 7A shows a firstwaveform 701 that represents thermal information from the first row ofmonitored volumes 610 and a second waveform 705 that represents thermalinformation from the second row of monitored volumes 620 as the human601 walks through the monitored space 600. As the human 601 passes intothe first monitored volume 611, the voltage of the first waveform 701begins to rise to the peak 702. Then as the human 601 passes from thefirst monitored volume 611 into the third monitored volume 621, thevoltage of the first waveform 701 begins to fall, and the voltage of thesecond waveform 705 begins to rise to the peak 706. As the human 601passes from the third monitored volume 621 to the second monitoredvolume 612, the second waveform 705 begins to fall and the firstwaveform 701 falls to a valley 703. As the human 601 passes from thesecond monitored volume 612 to the fourth monitored volume 622 the firstwaveform 701 begins to rise and the second waveform 705 falls to thevalley 707, and then begins to rise again as the human 601 leaves thefourth monitored volume 622.

The first waveform 701 shows a half-period 704 which is based on thepitch 631 of the first row of monitored volumes 610 and the speed atwhich the human 601 traverses the monitored space 600. Because thesecond row of monitored volumes 620 has the same pitch as the first row610, and the human is moving through the second row of monitored volumes620 at the same speed that she is moving through the first row, thehalf-period 708 of the second waveform 705 is about the same as thehalf-period 704 of the first waveform 701. But because the second row ofmonitored volumes 620 has a non-zero offset 633 from the first row 610,the second waveform 705 has a phase delay 709 from the first waveform701. By detecting that the first waveform 701 and the second waveform705 are separated by a phase delay 709 that corresponds to the criticalphase angle calculated from the pitch 631 of the monitored volumes, andthe non-zero offset 633 of the second row of monitored volumes 620 fromthe first row of monitored volumes 610, an animal-immune motiondetection can be achieved by embodiments.

FIG. 7B shows a first waveform 711 that represents thermal informationfrom the first row of monitored volumes 610 and a second waveform 715that represents thermal information from the second row of monitoredvolumes 620 as the animal 602 walks through the monitored space 600. Asthe animal 602 passes under the first monitored volume 611, the voltageof the first waveform 711 is unaffected. Then as the animal 602 passesinto the third monitored volume 621, the voltage of the second waveform715 begins to rise to the peak 716. As the animal 602 passes from thethird monitored volume 621 and under the second monitored volume 612,the second waveform 715 begins to fall and the first waveform 711remains unaffected. As the animal 602 enters into the fourth monitoredvolume 622, the second waveform 715 falls to the valley 717, and thenbegins to rise again as the animal 602 leaves the fourth monitoredvolume 622.

The first waveform 711 is unaffected by the animal 602, because theanimal 602 is not tall enough to enter the first row of monitoredvolumes 610. The second waveform 711 shows a half-period 718 which isbased on the pitch of the first row of monitored volumes 610 and thespeed at which the animal 602 traverses the monitored space 600. Bydetecting that the difference between the two waveforms 711, 715 isgreater than a predetermined threshold, a minor motion detection can beachieved by embodiments. Some embodiments may perform additional signalprocessing on the two waveforms to smooth the difference or otherwiseprocess the individual waveforms of the difference waveform to reducefalse positives or increase detection rates.

While it is not shown in FIG. 7A/B, an overall change in ambienttemperature, or a mechanical shock could result in the two waveformsfrom the infrared detector being nearly equivalent, with no phase delay,as shown in FIG. 2B. By detecting that the first waveform and the secondwaveform do not have a phase difference, and that the difference betweenthe two waveforms does not exceed a predetermined threshold, falsepositives can be reduced by embodiments.

FIG. 6A/B and FIG. 7A/B together show how a method of discriminatinghuman motion from animal motion within an infrared detection area, ormonitored space 600, is implemented in some embodiments. Infraredintensity from within the infrared detection area 600 is sensed. Atleast two stacked non-overlapping detection tiers, 610, 620 are providedwithin the infrared detection area 600. Each detection tier 610, 620includes a plurality of non-overlapping monitored volumes. The pluralityof non-overlapping monitored volumes of the at least two detection tiers610, 620 are shifted from each other in a horizontal direction by anoffset 633. A change in the infrared intensity that occurs in only onedetection tier of the at least two stacked non-overlapping detectiontiers is ignored by some embodiments, as it may have been caused by ananimal, although some embodiments may generate a minor motionindication, or in some embodiments in some modes a general motionindication, in response to a change in only one detection tier. A motionindication indicative of a presence of a human is generated byembodiments in response to registering sufficient changes in theinfrared intensity on vertically adjacent detection tiers of the atleast two stacked detection tiers having a phase relationship thatcorresponds to a critical phase angle. The critical phase angle can becalculated as 180 degrees times a percentage of a pitch 631 of thenon-overlapping monitored volumes represented by the offset 633, and isgreater than 0 degrees. In some embodiments, the critical phase angle isbetween about 10 degrees and about 80 degrees or between about 100degrees and about 170 degrees. Changes in the infrared intensity onvertically adjacent detection tiers of the at least two stackeddetection tiers having a phase relationship that does not correspond tothe critical phase angle are ignored by embodiments. The method isimplemented by computer code in some embodiments, which is stored on atleast one machine readable medium.

FIG. 8 shows a side view 801 and a top view 802, respectively, of anembodiment of monitored volumes for a motion sensor 810 in a room 800.Side view 801 shows a vertical planar cross-section of the room 800 asshown by the cross-section line A:A in top view 802. Looking first atthe side view 801, the motion sensor 810 is mounted on a wall of theroom 800. The motion sensor 810 can be mounted at any height, dependingon the embodiment, but in the embodiment shown, the motion sensor 810 ismounted at a height somewhat above the average height of a human, orabout 2 meters (m) above the floor. The motion sensor 810 monitorsseveral tiers, or rows, of monitored volumes that project from themotion sensor 810 at different elevations. In the side view 801, themonitored volumes without hatch lines, such as monitored volume 824, arebehind the cross-sectional plane A:A, and the monitored volumes with thehatch lines, such as monitored volume 834, are intersected by thecross-sectional plane A:A. The various tiers intersect the floor of theroom 800 in arcs, as shown in the top view 802. The locations where theeven numbered tiers hit the floor are shown without hatch lines, and thelocations where the odd numbered tiers hit the floor are shown withhatch lines in the top view 802.

Looking now at both the side view 801 and the top view 802 together, thehighest tier 820, which includes the monitored volume 824 and isconsidered an even numbered tier, does not hit the floor of the room 800due to its small angle of downward deflection and the size of the room.The tier 820 includes other monitored volumes that are not shown becausethey don't hit the floor of the room 800, but are consistent with thepattern of the other even numbered tiers. Monitored volume 834 is a partof the second highest tier 830, which is considered an odd numberedtier, and also includes other monitored volumes that do not hit thefloor of the room 800, but are consistent with the pattern of the otherodd numbered tiers. The next even numbered tier 840 includes monitoredvolumes 841-846, the next odd numbered tier 850 includes monitoredvolumes 851-856, and the next even numbered tier 860 includes monitoredvolumes 861-866. Additional alternating odd tiers 871, 873, 875, 877 andeven tiers 872, 874, 876 each include a set of monitored volumes. Thenumber of tiers and number of monitored volumes per tier shown in FIG. 8are shown as an example, but any number of tiers and monitored volumesper tier can be used in various embodiments. Other embodiments caninclude more, or fewer, tiers, or rows, of monitored volumes. Otherembodiments can also include more or fewer monitored volumes in a tier.Some embodiments may include tiers with different numbers of monitoredvolumes than other tiers.

In the embodiment shown, a first set of monitored volumes includes twoor more tiers of monitored volumes, the even tiers in this example, anda second set of monitored volumes that includes two or more tiers ofmonitored volumes, the odd tiers in this example, which are interleavedwith the two or more tiers of monitored volumes of the first set ofmonitored volumes. In at least one embodiment, infrared rays from thefirst set of monitored volumes, or even tiers, are directed onto a firstrow, or set, of detector elements on an infrared detector in the motionsensor 810, and infrared rays from the second set of monitored volumes,or odd tiers, are directed onto a second row, or set, of detectorelements on an infrared detector in the motion sensor 810.

The monitored volumes of a tier are spaced at a pitch 811, which can bemeasured in degrees for some embodiments. In the embodiment shown, thepitch 811 is about 15°, but the pitch can be any angle, depending on theembodiment. In embodiments, at least some of the tiers of both sets ofmonitored volumes have about the same pitch 811. The monitored volumesof the second set of monitored volumes are offset from the monitoredvolumes of the first set of monitored volumes by an offset 813. Theoffset can be any angle, but is no greater than the pitch in manyembodiments. In the embodiment, shown the offset is about 5°, which isone third of the pitch.

A human 891 and an animal 893 are both shown in FIG. 8 but are to beconsidered independently, as if the other were not there, in thefollowing discussions. As the human 891 moves through the room 800 inthe direction 892, she passes through multiple monitored volumes ofmultiple tiers. At her initial location, the human 891 is intersectingmonitored volume 854 of tier 850 and monitored volume 834 of tier 830,which are part of the second set of monitored volumes. Infraredradiation generated by the warmth of her body is directed from the twomonitored volumes 834, 854 onto one or more detector elements in themotion sensor 810 In the embodiment, shown, infrared rays from themonitored volume 834 and the monitored volume 854 are both directed ontoa second detector element of a second row of detector elements whichgenerates a negative voltage in response to warming.

As the human 891 moves in the direction 892, she moves out of themonitored volume 854 and monitored volume 834, and into monitored volume864, monitored volume 844, and monitored volume 824, which are a part ofthe first set of monitored volumes. In the embodiment shown, infraredrays from the monitored volume 864, monitored volume 844, and monitoredvolume 824 are directed onto a second detector element of a first row ofdetector elements that generates a negative voltage in response towarming.

As the human 891 continues to move in the direction 892, she moves outof the monitored volumes of the first set of monitored volumes and backinto monitored volumes of the second set of monitored volumes, monitoredvolume 855 of tier 850 and a monitored volume of tier 830, from whichinfrared rays are directed onto a first detector element of the secondrow of detector elements that generates a positive voltage in responseto warming. As the human 891 continues to move in the direction 892, shemoves out of the monitored volumes of the second set of monitoredvolumes and back into monitored volumes of the first set of monitoredvolumes, monitored volume 865 of tier 860, monitored volume 845 of tier840, and a monitored volume of tier 820, from which infrared rays aredirected onto a first detector element of the first row of detectorelements that generates a positive voltage in response to warming.

So as the human 891 moves through the room 800 in the direction 892, theinfrared detector in the motion sensor 810 generates two waveforms, onefor each row of detector elements. The two waveforms have about the sameshape, but have a different phase, due to the offset 813 between the twosets of monitored volumes. The two waveforms created by the motion ofthe human 891 have a phase relationship that is about 60° different,which corresponds to the critical phase angle calculated by dividing theoffset 813 by the pitch 811 and multiplying by 180°, (5+15)×180°=60°.Because the two waveforms have a phase difference that corresponds tothe critical angle, motion of a human 891 is detected, and ananimal-immune motion indication, which may also be referred to as amajor motion indication or human motion indication, is generated whichcan be one or more of an audible indication, such as a siren or warningvoice, a visual indication, such as turning on a light, or a actuating astrobe light or rotating light, generating an indication on a wiredcircuit, such as closing a switch or sending an ethernet message, and/orsending a radio frequency message, such as a message sent over a Wi-Fi(IEEE 802.11) network or Zigbee (IEEE 802.15) network.

Looking now at motion of an animal 893 instead of the human 891, theanimal 893 moves through the room 800 in direction 894. In its initialposition, the animal 893 intersects monitored volume 854, with verylittle of the animal 893 intersecting with any other monitored volumes.As the animal 893 moves in the direction 894, he moves out of themonitored volume 854 and eventually into the monitored volume 855. Asthe infrared radiation generated by the warmth of the body of the animal893 is directed onto the infrared detector of the motion sensor 810, avoltage is generated by the second row of detector elements, but not bythe first row of detector elements, because there is very littleinfrared radiation from the animal 893 picked up from the first tier ofmonitored volumes and directed onto the first row of detector elements.So the two waveforms generated by the infrared detector in the motionsensor 810 have a different shape, and therefore do not really have aphase relationship.

So human motion is detected in embodiments by receiving a first outputof an infrared detector representing a warm body passing through a firsttier of monitored volumes, and receiving a second output of the infrareddetector representing the warm body passing through a second tier ofmonitored volumes. The second tier of monitored volumes are locatedbelow the first tier of monitored volumes with a horizontal offset fromthe first tier of monitored volumes. An animal-immune motion indicationis generated by embodiments based on a phase difference between thefirst output and the second output of the infrared detectorcorresponding to a critical phase angle. The critical phase angle canvary between embodiments, but is greater than 0° and is between about10° and about 170° in some embodiments. Depending on the embodiment, theanimal-immune motion indication can include a visual indication, anaudible indication and/or sending a radio frequency message. In someembodiments, it is determined whether a smoothed difference between thefirst output and the second output exceeds a predetermined value aftercompensating for background levels of the first output and secondoutput, and a minor motion indication generated in response to thesmoothed difference exceeding the predetermined value. Some embodimentsalso include obtaining a mode setting for a minor motion detection whichis used to determine whether or not to generate a minor motionindication. In some embodiments the human motion detection isimplemented using a computer program product that includes at least onenon-transitory computer readable storage medium having computer readableprogram code embodied therewith.

FIG. 9A-C show embodiments of optical systems for use in a motionsensor. FIG. 9A shows an embodiment that uses lenses to generate theoffset between tiers of monitored volumes. The infrared detector 900 ofFIG. 9A has a first row of two detector elements, detector element 901and detector element 902, and a second row of two detector elements,detector element 903 and detector element 904, that is aligned with thefirst row of detector elements. The first detector element 901 of thefirst row is directly above the first detector element 903 of the secondrow, and the second detector element 902 of the first row is directlyabove the second detector element 904 of the second row. The front ofthe infrared detector 900 is shown.

FIG. 9A includes a top view 910 and a side view 920 of a few of thelight paths for a subset of monitored volumes of an embodimentrepresented by projections of the monitored volumes on a wall. The firsttier of monitored volumes includes monitored volume 913, monitoredvolume 914, monitored volume 923, and monitored volume 924. The secondtier of monitored volumes includes monitored volume 911, monitoredvolume 912, monitored volume 921, and monitored volume 922. Both thefirst tier of monitored volumes and the second tier of monitored volumesare shown in the top view 910 but other lower tiers are not shown in thetop view 910. The side view 920 shows the end monitored volume of fourtiers, the first tier's end monitored volume 924, the second tier's endmonitored volume 922, the third tier's end monitored volume 928 and thefourth tier's end monitored volume 926. Embodiments can includeadditional monitored volumes in each tier and/or more tiers.

In the embodiment of FIG. 9A, lenses, such as first lens 905 and secondlens 906 direct electromagnetic radiation, such as infrared light, fromthe monitored volumes onto the detector elements of the infrareddetector 900. The top of the infrared detector 900 is shown in the topview 910 and the left side of the infrared detector 900 is shown in theside view 920. The front of the infrared detector 900 is facing to theright in both the top view 910 and the side view 920. The first lens 905is positioned to direct light from a portion of the first tier ofmonitored volumes onto the second row of detector elements, so thatlight from the monitored volume 913 is directed onto detector element903 and light from the monitored volume 914 is directed onto detectorelement 904. The second lens 906 is positioned to direct light from anoffset portion of the second tier of monitored volumes onto the firstrow of detector elements of the infrared detector 900, so that lightfrom the monitored volume 911 is directed onto detector element 901 andlight from the monitored volume 912 is directed onto detector element902. Other lenses 907 direct other portions of the first and secondtiers of monitored volumes onto the second and first rows of detectorelements, respectively in the embodiment of FIG. 9A, so that light fromthe monitored volume 921 is directed onto detector element 901, lightfrom the monitored volume 922 is directed onto detector element 902,light from the monitored volume 923 is directed onto detector element903, and light from the monitored volume 924 is directed onto detectorelement 904.

Additional lenses direct portions of other tiers of monitored volumesonto the detector elements. In the example shown in the side view 920 ofthe embodiment of FIG. 9A, lenses 908 direct light from the monitoredvolume 928, as well as another monitored volume of that tier (not shownbut behind monitored volume 928 in side view 920) on the second row ofdetector elements so the light from the monitored volume 928 is directedonto detector element 904 and the other monitored volume of that tier isdirected onto detector element 903. The lenses 908 also direct lightfrom the monitored volume 926, as well as another monitored volume ofthat tier (not shown but behind monitored volume 926 in side view 920)onto the first row of detector elements so the light from the monitoredvolume 926 is directed onto detector element 902 and the light from theother monitored volume of that tier is directed onto detector element901.

A large number of individual lenses can be used in an embodiment,although some embodiments utilize one or more Fresnel lenses to directthe electromagnetic radiation as shown in FIG. 9A. For at least someembodiments utilizing an infrared detector with two rows of two aligneddetector elements, an embodiment having four tiers of four monitoredvolumes includes at least eight lenses or different Fresnel elements.For at least some embodiments having 12 tiers of 6 monitored volumes asshown in FIG. 8, at least 36 lenses, or different Fresnel elements, areused. Some embodiments use one lens for each monitored volume.

In the embodiment of FIG. 9A, lenses are used to create an offsetbetween tiers of monitored volumes even though there is no offsetbetween rows, or sets, of detector elements on the infrared detector. Soin some embodiments of a motion sensor, an infrared detector includes afirst set of detector elements, and a second set of detector elementsthat are offset from the first set in a first detector direction (i.e. adirection on the substrate of the infrared detector) to create two rowsof detector elements. The second set of detector elements are positionedwithout a significant offset from the first set of detector elements ina second detector direction that is orthogonal to the first detectordirection (i.e. the sets, or rows, are aligned). In such embodiments,the optical system includes a first set of optical elements to directthe electromagnetic energy from the first set of monitored volumes ontothe first set of detector elements on a first path having a firstgeometry. Lens 905 is an example of a lens of the first set of opticalelements that directs electromagnetic energy from the first tier ofmonitored volumes onto the second row of detector elements on the pathwith the geometry shown by the dashed lines. The optical system alsoincludes a second set of optical elements to direct the electromagneticenergy from the second set of monitored volumes onto the second set ofdetector elements on a second path having a second geometry that isdifferent than the first geometry. Lens 906 is an example of a lens ofthe second set of optical elements that directs electromagnetic energyfrom the second tier of monitored volumes on the first row of detectorelements on the path with the geometry shown by the solid lines. Theembodiment shown in FIG. 9A might be used for a set of monitored volumescovering a small deflection angle. Embodiments may also include ahorizontal blocking wall to separate the optical paths of the upper rowof detector elements 901, 902 from the optical paths of the lower row ofdetector elements 903, 904. The horizontal blocking wall can be used toprevent lens 905 from directing electromagnetic energy from anadditional monitored volume onto the upper row of detector elements 901,902 and to prevent lens 906 from directing electromagnetic energy froman additional monitored volume onto the lower row of detector elements903, 904.

FIG. 9B shows an embodiment that utilizes an offset between rows ofdetector elements to generate the offset between tiers of monitoredvolumes. The infrared detector 930 of FIG. 9B has a first row of twodetector elements, detector element 931 and detector element 932, and asecond row of two detector elements, detector element 933 and detectorelement 934, that have an offset from the first row of detector elementsin a direction that is parallel to the row direction. The first detectorelement 933 of the second row is offset from the first detector element931 of the first row, that is shifted in the same direction as thedirection of a row (horizontal as shown for the infrared detector 930 ofFIG. 9B). The second detector element 934 of the second row is alsooffset from the second detector element 932 of the first row. The frontof the infrared detector 930 is shown.

FIG. 9B includes a top view 940 and a side view 950 of a few of thelight paths for a subset of monitored volumes of an embodimentrepresented by projections of the monitored volumes on a wall. The firsttier of monitored volumes includes monitored volume 943, monitoredvolume 944, monitored volume 953, and monitored volume 954. The secondtier of monitored volumes includes monitored volume 941, monitoredvolume 942, monitored volume 951, and monitored volume 952. Both thefirst tier of monitored volumes and the second tier of monitored volumesare shown in the top view 940 but other lower tiers are not shown in thetop view 940. The side view 950 shows the end monitored volume of fourtiers, the first tier's end monitored volume 954, the second tier's endmonitored volume 952, the third tier's end monitored volume 958 and thefourth tier's end monitored volume 956. Embodiments can includeadditional monitored volumes in each tier and/or more tiers.

In the embodiment of FIG. 9B, lenses, such as lenses 935, 937, 938,direct electromagnetic radiation, such as infrared light, from themonitored volumes onto the detector elements of the infrared detector930. The top of the infrared detector 930 is shown in the top view 940and the left side of the infrared detector 930 is shown in the side view950. The front of the infrared detector 930 is facing to the right inboth the top view 940 and the side view 950. The first lens 935 ispositioned to light from a portion of the first and second tiers ofmonitored volumes onto the infrared detector 930, so that light from themonitored volume 943 is directed onto detector element 933, light fromthe monitored volume 944 is directed onto detector element 934, lightfrom the monitored volume 941 is directed ed onto detector element 931,and light from the monitored volume 942 is directed onto detectorelement 932. Another lens 937 directs another portion of the first andsecond tiers of monitored volumes onto the infrared detector 930, sothat light from the monitored volume 951 is directed onto detectorelement 931, light from the monitored volume 952 is directed ontodetector element 932, light from the monitored volume 953 is directedonto detector element 933, and light from the monitored volume 954 isdirected onto detector element 934.

Other lenses direct portions of other pairs of tiers of monitoredvolumes onto the infrared detector 930. In the example shown in the sideview 950 of the embodiment of FIG. 9B, lens 938 directs light from themonitored volume 958 and monitored volume 956, as well as othermonitored volumes of those tiers (not shown but behind monitored volumes958, 956 in side view 950) onto the infrared detector 930 so the lightfrom the monitored volume 958 is directed onto detector element 934,light an adjacent monitored volume of that tier is directed ontodetector element 933, light from the monitored volume 956 is directedonto detector element 932, and light from an adjacent monitored volumeof that tier is directed onto detector element 931.

A large number of individual lenses can be used in an embodiment,although some embodiments utilize one or more Fresnel lenses to directthe electromagnetic radiation as shown in FIG. 9B. For at least someembodiments utilizing an infrared detector with two rows of two aligneddetector elements, an embodiment having four tiers of four monitoredvolumes includes at least four lenses or different Fresnel elements. Forat least some embodiments having 12 tiers of 6 monitored volumes asshown in FIG. 8, at least 18 lenses, or different Fresnel elements, areused. Some embodiments use one lens for each monitored volume.

In the embodiment of FIG. 9B, an offset between rows of detectorelements on the infrared detector is used to create an offset betweentiers of monitored volumes. So in some embodiments of a motion sensor,an infrared detector includes a first set of detector elements, and asecond set of detector elements that have a first offset from the firstset in a first detector direction (i.e. a direction on the substrate ofthe infrared detector) to create two rows of detector elements. Thesecond set of detector elements are positioned to have a second offsetfrom the first set of detector elements in a second detector directionthat is orthogonal to the first detector direction (i.e. the sets, orrows, are offset from each other).

FIG. 9C shows an embodiment that uses reflecting elements, reflectors,or mirrors, to generate the offset between tiers of monitored volumes.The infrared detector 960 of FIG. 9C has a first row of two detectorelements, detector element 961 and detector element 962, and a secondrow of two detector elements, detector element 963 and detector element964, that is aligned with the first row of detector elements. The firstdetector element 961 of the first row is directly above the firstdetector element 963 of the second row, and the second detector element962 of the first row is directly above the second detector element 964of the second row. The front of the infrared detector 960 is shown.

FIG. 9C includes a top view 980 and a side view 990 of a few of thelight paths for a subset of monitored volumes of an embodimentrepresented by projections of the monitored volumes on a wall. The firsttier of monitored volumes includes monitored volume 983, monitoredvolume 984, monitored volume 993, and monitored volume 994. The secondtier of monitored volumes includes monitored volume 981, monitoredvolume 982, monitored volume 991, and monitored volume 992. Both thefirst tier of monitored volumes and the second tier of monitored volumesare shown in the top view 980 but other lower tiers are not shown in thetop view 980. The side view 990 shows the end monitored volume of fourtiers, the first tier's end monitored volume 994, the second tier's endmonitored volume 992, the third tier's end monitored volume 998 and thefourth tier's end monitored volume 996. Embodiments can includeadditional monitored volumes in each tier and/or more tiers.

In the embodiment of FIG. 9C, one or more reflecting elements, only someof which are shown, are used to reflect light from the monitored volumesto the infrared detector 960 where an offset between rows of detectorelements on the infrared detector 960 is used to generate the offsetbetween tiers of monitored volumes. The top of the infrared detector 960is shown in the top view 980 and the right side of the infrared detector960 is shown in the side view 990. The front of the infrared detector960 is facing to the left and slightly down in both the top view 980 andthe side view 990. The first reflecting element 973 is positioned toreflect light from a portion of the first and second tiers of monitoredvolumes on the infrared detector 960, so that light from the monitoredvolume 981 is reflected to detector element 961, light from themonitored volume 982 is reflected to detector element 962, light fromthe monitored volume 983 is reflected to detector element 963, and lightfrom the monitored volume 984 is reflected to detector element 964.Another reflecting element 974 reflects another portion of the first andsecond tiers of monitored volumes on the infrared detector 960, so thatlight from the monitored volume 991 is reflected to detector element961, light from the monitored volume 992 is reflected to detectorelement 962, light from the monitored volume 993 is reflected todetector element 963, and light from the monitored volume 994 isreflected to detector element 964.

Additional reflecting elements reflect portions of other tiers ofmonitored volumes on the infrared detector 960. In the example shown inthe side view 990 of the embodiment of FIG. 9C, reflecting element 976reflects light from the monitored volume 998, as well as anotheradjacent monitored volume of that tier (not shown but behind monitoredvolume 998 in side view 990) on the first row of detector elements sothe light from the monitored volume 998 is reflected to detector element962 and the adjacent monitored volume of that tier is directed ontodetector element 961. The reflecting element 976 also reflects lightfrom the monitored volume 996, as well as another adjacent monitoredvolume of that tier (not shown but behind monitored volume 996 in sideview 990) on the second row of detector elements so the light from themonitored volume 996 is reflected to detector element 964 and the otheradjacent monitored volume of that tier is directed onto detector element963.

A large number of individual reflecting elements can be used in anembodiment, which may also include one or more lenses or Fresnel lenses.For at least some embodiments utilizing an infrared detector with tworows of two offset detector elements, an embodiment having four tiers offour monitored volumes includes at least four reflecting elements. Forat least some embodiments having 12 tiers of 6 monitored volumes asshown in FIG. 8, at least 18 reflecting elements, are used. Someembodiments use an individual reflecting element for each monitoredvolume.

In the embodiment of FIG. 9C, reflecting elements are used to directlight from offset monitored volumes onto the infrared detector 960having offset between rows of detector elements. In other embodiments,reflecting elements are used create an offset between tiers of monitoredvolumes even though there is no offset between rows, or sets, ofdetector elements on the infrared detector.

The optical system of a motion sensor can use any combination ofconventional lenses, Fresnel lenses, compound lenses, diffractivelenses, reflecting elements, focusing mirrors, diffractive mirrors,planar reflectors, slits, light guides, filters, optical coatings,arrays of any of the aforementioned optical elements, or any other typeof optical component, to direct electromagnetic radiation from monitoredvolumes onto detector elements of an infrared detector, depending on theembodiment. An offset between tiers, rows, or sets, of monitored volumescan be created using an offset between rows, or sets, of detectorelements on an infrared detector, by using the optical system of themotion sensor, or by a combination of the geometry of the infrareddetector and the characteristics of the optical system, depending on theembodiment.

FIG. 10 shows a block diagram of an embodiment of a motion sensor 1000.The motion sensor 1000 includes an infrared detector 1002 that has afirst set of detector elements and a second set of detector elements.The motion sensor 1000 also includes an optical system 1004 to directelectromagnetic energy 1006 from a first set of monitored volumes ontothe first set of detector elements and to direct electromagnetic energy1008 from a second set of monitored volumes onto the second set ofdetector elements. In embodiments, the electromagnetic energy directedonto the detector elements includes infrared light. The first set ofmonitored volumes are spaced at a pitch and the second set of monitoredvolumes are spaced at the same pitch. The second set of monitoredvolumes have an offset from the first set of monitored volumes in adirection parallel to the pitch, as shown in FIG. 8. In some embodimentsthe optical system 1004 creates the offset between the two sets ofmonitored volumes, and in some embodiments the offset between the twosets of monitored volumes is created by an offset between the two setsof detector elements on the infrared detector 1002. The offset can beany percentage of the pitch, depending on the embodiment, but in someembodiments, the offset is a non-quadrature offset, e.g. the offset isnot equal to 50% of the pitch. In some embodiments, the second set ofmonitored volumes have a second offset from the first set of monitoredvolumes in a second direction that is orthogonal to the first direction.The second offset can create two or more tiers of monitored volumeswhich may or may not be overlapping, depending on the embodiment.

The motion sensor 1000 of the embodiment of FIG. 10 also includescircuitry 1010 such as a processor 1011 coupled to the infrared detector1002. Memory 1012 which can store computer code 1020, is coupled to theprocessor 1011 in embodiments, and the processor 1011 can read thecomputer code 1020 from the memory 1012 and execute the computer code1020 to perform one or more of the methods described herein in someembodiments. A wireless network interface 1014 is coupled to an antenna1016 as well as to the processor 1011 to allow radio frequency messagesto be sent and/or received by the motion sensor 1000 over a wirelesscomputer network such as, but not limited to, a Wi-Fi network or aZigbee network. Other embodiments include different types of circuitry1010 that may or may not include a processor 1011, but may includespecialized hard-wired or specialized circuitry to perform one or moremethods described herein.

In embodiments, the circuitry 1010 receives first thermal informationabout the first set of detector elements of the motion sensor 1002 andsecond thermal information about the second set of detector elements ofthe motion sensor 1002. In embodiments the first thermal informationincludes thermal information from a first set of monitored volumes, andthe second thermal information that includes thermal information from asecond set of monitored volumes. In at least one embodiment, the firstset of monitored volumes includes a plurality of aligned rows ofmonitored volumes and the second set of monitored volumes includes aplurality of aligned rows of monitored volumes that are offset from therows of the first set and alternate with the rows of the first set.

The circuitry 1010 in some embodiments registers a first backgroundlevel for the first thermal information, and a second background levelfor the second thermal information. The circuitry 1010 then compares afirst waveform representing the first thermal information aftersubtracting the first background level to a second waveform representingthe second thermal information after subtracting the second backgroundlevel. In some embodiments, the background levels are not registered orcompensated for, as the steady-state condition of the environment can beassumed to be constant and/or any charge generated by the pyroelectriceffect has been discharged through leakage current in the infrareddetector. A first type of motion indication, which may be referred to asan animal-immune motion indication, a major motion indication, or ahuman motion indication, is generated by the circuitry 1010 if thesecond waveform corresponds to the first waveform with a phase shiftcorresponding to the offset. In some embodiments, the first type ofmotion indication includes a radio frequency message sent through theantenna 1016, a visual indication, and/or an audible indication. In someembodiments the circuitry 1010 also determines whether a smootheddifference between the first waveform and the second waveform exceeds apredetermined value, and generates a second type of motion indication ifthe smoothed difference exceeds the predetermined value. In someembodiments, the second type of motion indication, which may be referredto as a minor motion indication, a sedentary-human motion indication, asmall-animal motion indication, or a non-animal-immune motionindication, includes a radio frequency message sent through the antenna1016, a visual indication, and/or an audible indication.

In some embodiments, a mode setting is obtained by the circuitry 1010.The mode setting is set by a physical switch on the motion sensor 1000in some embodiments, but in other embodiments, the mode setting isreceived as a message over a wireless network through the antenna 1016.The mode setting in embodiments can be set to one of several differentstates, including a first state to detect major motion but not minormotion, a second state to detect either major or minor motion and notindicate a difference (e.g. a general motion detection), a third stateto detect minor motion but not major motion, a fourth state to detecteither major or minor motion and to report the difference, and a fifthstate to disable detection of any motion, minor or major. Variousembodiments can implement any subset of the five states described, aswell as other states. In embodiments implementing minor motiondetection, if the smoothed difference between the two waveforms exceedsthe predetermined value and the mode is set for minor motion detection,a motion indication is generated. If the mode setting has a state thatthe type of motion is to be reported, the motion indication generatedshows that type of motion detected, such as minor or major. If the modeis set to ignore animals (i.e. for major motion detection only), nomotion indication is generated in response to the smoothed differencebetween the two waveforms exceeding the predetermined value. In at leastone embodiment, the mode setting is included in a first message receivedthrough the antenna, the first type of motion indication, or majormotion indication, includes a second message sent through the antenna,and the second type of motion indication, or minor motion indication,includes a third message sent through the antenna. Each of the threemessages includes different content in at least some embodiments.

FIG. 11 shows a flow chart 1100 of an embodiment of a method to detectmotion. The motion detection starts at block 1101 and continues byreceiving a first output of an infrared detector representing a warmbody passing through a first tier of monitored volumes at block 1102. Asecond output of the infrared detector representing the warm bodypassing through a second tier of monitored volumes is received at block1103. In embodiments, the second tier of monitored volumes is locatedabove the first tier of monitored volumes with a horizontal offset fromthe first tier of monitored volumes. A phase difference between thefirst output and the second output of the infrared detector is checkedat block 1104. If the phase angle corresponds to a critical phase anglethat is greater than 0°, an animal-immune (major motion) indication isgenerated at block 1105 and the motion sensor continues to monitor formotion at block 1109. The critical phase angle of an embodiment is basedon a pitch of monitored volumes and the horizontal offset of the betweenthe tiers of monitored volumes. In some embodiments, the critical phaseangle is between about 10 degrees and about 170 degrees. In someembodiments, the critical phase angle is between about 10 degrees andabout 80 degrees or between about 100 degrees and about 170 degrees. Insome embodiments, the animal-immune motion indication includes a visualindication or an audible indication. In some embodiments, theanimal-immune motion indication includes a radio frequency message.

If, at block 1104, the phase angle does not correspond to the criticalphase angle, or if there is no phase relationship between the twooutputs, some embodiments check a mode setting to see if animaldetection has been enabled at block 1106. If animal detection has notbeen enabled, any minor motion indication is suppressed, and the motionsensor continues to monitor motion at block 1109. If animal detectionhas been enabled, it is determined whether a smoothed difference betweenthe first output and the second output exceeds a predetermined valueafter compensating, in some embodiments, for background levels of thefirst output and second output at block 1107. If the smoothed differenceexceeds the predetermined value, a minor motion indication is generatedat block 1108. In some embodiments, the major motion indication and theminor motion indication are different and provide information about thetype of motion detected. In other embodiments, the major motionindication and the minor motion indication are indistinguishable.

As will be appreciated by those of ordinary skill in the art, aspects ofthe various embodiments may be embodied as a system, method or computerprogram product. Accordingly, aspects of the present invention may takethe form of an entirely hardware embodiment, an entirely softwareembodiment (including firmware, resident software, micro-code, or thelike) or an embodiment combining software and hardware aspects that mayall generally be referred to herein as a “circuitry,” “block,” “motionsensor,” or “system.” Furthermore, aspects of the various embodimentsmay take the form of a computer program product embodied in one or morecomputer readable medium(s) having computer readable program code storedthereon.

Any combination of one or more computer readable storage medium(s) maybe utilized. A computer readable storage medium may be embodied as, forexample, an electronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or other like storagedevices known to those of ordinary skill in the art, or any suitablecombination of computer readable storage mediums described herein. Inthe context of this document, a computer readable storage medium may beany tangible medium that can contain, or store a program and/or data foruse by or in connection with an instruction execution system, apparatus,or device.

Computer program code for carrying out operations for aspects of variousembodiments may be written in any combination of one or more programminglanguages, including an object oriented programming language such asJava, Smalltalk, C++, or the like, and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. In accordance with various implementations, theprogram code may execute entirely on the processor of an embodiment,partly on the processor of an embodiment and partly on another processorthat may be local or remote to the motion sensor, or entirely on theremote computer or server. In the latter scenario, the remote computermay be connected to the user's computer through any type of network,including a local area network (LAN) or a wide area network (WAN), orthe connection may be made to an external computer (for example, throughthe Internet using an Internet Service Provider). Some embodiments maybe a stand-alone software package.

The computer program code, if executed by a processor causes physicalchanges in the electronic devices of the processor which change thephysical flow of electrons through the devices. This alters theconnections between devices which changes the functionality of thecircuit. For example, if two transistors in a processor are wired toperform a multiplexing operation under control of the computer programcode, if a first computer instruction is executed, electrons from afirst source flow through the first transistor to a destination, but ifa different computer instruction is executed, electrons from the firstsource are blocked from reaching the destination, but electrons from asecond source are allowed to flow through the second transistor to thedestination. So a processor programmed to perform a task is transformedfrom what the processor was before being programmed to perform thattask, much like a physical plumbing system with different valves can becontrolled to change the physical flow of a fluid.

Aspects of various embodiments are described with reference to flowchartillustrations and/or block diagrams of methods, apparatus, systems, andcomputer program products according to various embodiments disclosedherein. It will be understood that various blocks of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks. The computer program instructions may also beloaded onto a computer, other programmable data processing apparatus, orother devices to cause a series of operational steps to be performed onthe computer, other programmable apparatus or other devices to produce acomputer implemented process such that the instructions which execute onthe computer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and/or block diagrams in the figures help to illustratethe architecture, functionality, and operation of possibleimplementations of systems, methods and computer program products ofvarious embodiments. In this regard, each block in the flowchart orblock diagrams may represent a module, segment, or portion of code,which comprises one or more executable instructions for implementing thespecified logical function(s). It should also be noted that, in somealternative implementations, the functions noted in the block may occurout of the order noted in the figures. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts, or combinations of special purpose hardware andcomputer instructions.

Examples of various embodiments are described in the followingparagraphs:

An example infrared detector includes a substrate comprising apyroelectric material, a first set of detector elements positioned onthe substrate spaced a pitch distance apart, and a second set ofdetector elements positioned on the substrate spaced about the pitchdistance apart, wherein the second set of detector elements arepositioned with a non-quadrature offset from the first set of detectorelements. In some example infrared detectors the first set of detectorelements comprises at least two serially coupled detector elements, andthe second set of detector elements comprises at least two seriallycoupled detector elements. In some example infrared detectors the firstset of detector elements comprises a first row of detector elements, andthe second set of detector elements comprises a second row of detectorelements that is substantially non-overlapping with the first row. Insome example infrared detectors the non-quadrature offset is between 5%of the pitch distance and 45% of the pitch distance or between 55% ofthe pitch distance and 95% of the pitch distance. In some exampleinfrared detectors the non-quadrature offset is about one third or abouttwo thirds of the pitch distance. Some example infrared detectors alsoinclude a first output coupled to the first set of detector elements,and a second output coupled to the second set of detector elements. Someexample infrared detectors also include a ground terminal, wherein thefirst set of detector elements consists of a first detector element anda second detector element, the second set of detector elements consistsof a third detector element and a fourth detector element, said first,second, third and fourth detector elements each comprise a capacitorusing the substrate as a dielectric, the first output is connected to afirst terminal of the first detector element, a second terminal of thefirst detector element is connected to a first terminal of the seconddetector element, a second terminal of the second detector element isconnected to the ground terminal, the second output is connected to afirst terminal of the third detector element, a second terminal of thethird detector element is connected to a first terminal of the fourthdetector element, and a second terminal of the fourth detector elementis connected to the ground terminal. Some example infrared detectorsalso include a package, wherein the substrate is mounted in the packageand positioned to allow external electromagnetic energy to affect thesubstrate, at least one terminal accessible from outside of the package,and circuitry, mounted in the package and coupled to the at least oneterminal, the first set of detector elements, and the second set ofdetector elements, to detect a first pyroelectric effect on the firstset of detector elements and a second pyroelectric effect on the secondset of detector elements, and to provide information about the firstpyroelectric effect and the second pyroelectric effect at the at leastone terminal. In some example infrared detectors the circuitry comprisesat least one analog-to-digital converter, and the information about thefirst pyroelectric effect and the second pyroelectric effect at the atleast one terminal comprises digital data representing at least onevoltage waveform. In some example infrared detectors the circuitrycomprises a first transistor buffer coupled to the first set of detectorelements and a second transistor buffer coupled to the second set ofdetector elements, and the at least one terminal comprises a firstoutput terminal, a second output terminal, a power terminal, and aground terminal, and the information about the first pyroelectric effectcomprises a first analog voltage waveform at the first output terminal,and the information about the second pyroelectric effect comprises asecond analog voltage waveform at the second output terminal. Anycombination of elements described in this paragraph may be used invarious embodiments.

An example motion sensor includes an infrared detector comprising afirst set of detector elements and a second set of detector elements,and an optical system to direct electromagnetic energy from a first setof monitored volumes spaced at a pitch in a first direction onto thefirst set of detector elements and to direct electromagnetic energy froma second set of monitored volumes spaced at the pitch in the firstdirection onto the second set of detector elements, wherein the secondset of monitored volumes have an offset from the first set of monitoredvolumes in the first direction. In some example motion sensors, theelectromagnetic energy comprises infrared light. In some example motionsensors, the optical system comprises at least a Fresnel lens. In someexample motion sensors, the optical system comprises at a plurality ofreflecting elements. In some example motion sensors, the offset is anon-quadrature offset. In some example motion sensors, the second set ofmonitored volumes have a second offset from the first set of monitoredvolumes in a second direction that is orthogonal to the first direction.In some example motion sensors, the first set of monitored volumescomprises two or more tiers of monitored volumes, and the second set ofmonitored volumes comprises two or more tiers of monitored volumesinterleaved with the two or more tiers of monitored volumes of the firstset of monitored volumes. In some example motion sensors, the second setof detector elements are positioned with a first offset from the firstset of detector elements in a first detector direction on a pyroelectricsubstrate, and the second set of detector elements are positioned at asecond offset from the first set of detector elements in a seconddetector direction on the pyroelectric substrate that is orthogonal tothe first detector direction. In some example motion sensors, the secondset of detector elements are positioned without a significant offsetfrom the first set of detector elements in a first detector direction ona pyroelectric substrate, and the second set of detector elements arepositioned at an offset from the first set of detector elements in asecond detector direction on the pyroelectric substrate that isorthogonal to the first detector direction, and the optical systemcomprises a first set of optical elements to direct the electromagneticenergy from the first set of monitored volumes onto the first set ofdetector elements on a first path having a first geometry, and a secondset of optical elements to direct the electromagnetic energy from thesecond set of monitored volumes onto the second set of detector elementson a second path having a second geometry that is different than thefirst geometry. Some example motion sensors also include circuitry toreceive first thermal information about the first set of detectorelements, and second thermal information about the second set ofdetector elements, compare a first waveform representing the firstthermal information to a second waveform representing the second thermalinformation, and generate a first type of motion indication if thesecond waveform corresponds to the first waveform with a phase shiftcorresponding to the offset. Some example motion sensors also includecircuitry to register a first background level for the first thermalinformation, and a second background level for the second thermalinformation, subtract the first background level from the first thermalinformation to create the first waveform, and the second backgroundlevel from the second thermal information to create the second waveform.Some example motion sensors also include an antenna coupled to thecircuitry, wherein the first type of motion indication comprises a radiofrequency message sent through the antenna. In some example motionsensors the second set of monitored volumes have a second offset fromthe first set of monitored volumes in a second direction that isorthogonal to the first direction, and the motion sensor furthercomprises circuitry to determine whether a smoothed difference betweenthe first waveform and the second waveform exceeds a predeterminedvalue, and generate a second type of motion indication if the smootheddifference exceeds the predetermined value. Some example motion sensorsalso include circuitry to receive a mode setting for animal detection,determine whether a smoothed difference between the first waveform andthe second waveform exceeds a predetermined value, generate a secondtype of motion indication if the smoothed difference exceeds thepredetermined value and the mode is set for animal detection, andsuppress the second type of motion indication if the mode is not set foranimal detection. Some example motion sensors also include an antennacoupled to the circuitry, wherein the mode setting is included in afirst message received through the antenna, the first type of motionindication comprises a second message sent through the antenna, and thesecond type of motion indication comprises a third message sent throughthe antenna. Any combination of elements described in this paragraph maybe used in various embodiments.

Another example motion sensor includes an infrared detector to providefirst thermal information from a first row of monitored volumes having apitch and second thermal information from a second row of monitoredvolumes having the pitch and shifted in a direction parallel to thefirst row by an offset, and circuitry, coupled to the infrared detector,to detect a phase relationship of waveforms extracted from the firstthermal information and the second thermal information, and to generatean animal-immune motion indication if the phase relationship correspondsto a critical phase angle, wherein the critical phase angle is greaterthan 0 degrees, and is based on the offset and the pitch. In someexample motion sensors the critical phase angle is between 10 degreesand 80 degrees or between 100 degrees and 170 degrees. In some examplemotion sensors the critical phase angle is 180 degrees times apercentage of the pitch represented by the offset. In some examplemotion sensors the first row of monitored volumes and the second row ofmonitored volumes are substantially non-overlapping. Some example motionsensors also include circuitry, coupled to the infrared detector, todetect a smoothed difference between the waveforms extracted from thefirst thermal information and the second thermal information, and togenerate a minor motion indication if the smoothed difference exceeds apredetermined value. In some example motion sensors the first thermalinformation includes thermal information from a first plurality ofaligned rows of monitored volumes that includes the first row ofmonitored volumes, and the second thermal information includes thermalinformation from a second plurality of aligned rows of monitored volumesthat includes the second row of monitored volumes, wherein the firstplurality of aligned rows of monitored volumes alternate with the secondplurality of aligned rows of monitored volumes. In some example motionsensors the animal-immune motion indication comprises a visualindication or an audible indication. In some example motion sensors theanimal-immune motion indication comprises a radio frequency message. Anycombination of elements described in this paragraph may be used invarious embodiments.

An example method of detecting motion includes receiving a first outputof an infrared detector representing a warm body passing through a firsttier of monitored volumes, receiving a second output of the infrareddetector representing the warm body passing through a second tier ofmonitored volumes, wherein the second tier of monitored volumes arelocated above the first tier of monitored volumes with a horizontaloffset from the first tier of monitored volumes, and generating ananimal-immune motion indication based on a phase difference between thefirst output and the second output of the infrared detectorcorresponding to a critical phase angle, wherein the critical phaseangle is greater than 0 degrees. In some example methods the criticalphase angle is between 10 degrees and 170 degrees. In some examplemethods the critical phase angle is between 10 degrees and 80 degrees orbetween 100 degrees and 170 degrees. In some example methods theanimal-immune motion indication comprises a visual indication or anaudible indication. In some example methods the animal-immune motionindication comprises a radio frequency message. Some example methodsalso include determining whether a smoothed difference between the firstoutput and the second output exceeds a predetermined value, andgenerating a minor motion indication in response to the determining thatthe smoothed difference exceeds the predetermined value. Some examplemethods also include compensating for background levels of the firstoutput and second output in calculation of the smoothed difference. Someexample methods also include obtaining a setting for a mode for animaldetection, and determining whether a smoothed difference between thefirst output and the second output exceeds a predetermined value, and inresponse to the smoothed difference exceeding the predetermined value,generating a minor motion indication if the mode is set for animaldetection, and suppressing the minor motion indication if the mode isnot set for animal detection. In some example methods the minor motionindication and the animal-immune motion indication areindistinguishable. In some example methods the obtaining the setting forthe mode for animal detection comprises receiving the setting though awireless network, the animal-immune motion indication comprises a firstmessage sent through the wireless network, and the minor motionindication comprises a second message sent through the wireless network.Any combination of elements described in this paragraph may be used invarious embodiments. Any example method may be implemented, at least inparty, using at least one machine readable medium comprising one or moreinstructions that in response to being executed on a computing devicecause the computing device to carry out a method according to thisparagraph.

An example computer program product for detecting motion includes atleast one non-transitory computer readable storage medium havingcomputer readable program code embodied therewith, the computer readableprogram code comprising computer readable program code to receive afirst output of an infrared detector representing a warm body passingthrough a first tier of monitored volumes, computer readable programcode to receive a second output of the infrared detector representingthe warm body passing through a second tier of monitored volumes,wherein the second tier of monitored volumes are located below the firsttier of monitored volumes with a horizontal offset from the first tierof monitored volumes, and computer readable program code to generate ananimal-immune motion indication based on a phase difference between thefirst output and the second output of the infrared detectorcorresponding to a critical phase angle that is greater than 0 degrees.In some example computer program products the critical phase angle isbetween 10 degrees and 170 degrees. In some example computer programproducts the critical phase angle is between 10 degrees and 80 degreesor between 100 degrees and 170 degrees. Some example computer programproducts also include computer readable code to generate a visualindication or an audible indication as at least a part of theanimal-immune motion indication. Some example computer program productsalso include computer readable code to send a radio frequency message asat least a part of the animal-immune motion indication. Some examplecomputer program products also include computer readable code todetermine whether a smoothed difference between the first output and thesecond output exceeds a predetermined value after compensating forbackground levels of the first output and second output, and computerreadable code to generate a minor motion indication, in response to thesmoothed difference exceeding the predetermined value. Some examplecomputer program products also include computer readable code to obtaina setting for a mode for animal detection, computer readable code todetermine whether a smoothed difference between the first output and thesecond output exceeds a predetermined value after compensating forbackground levels of the first output and second output, and computerreadable code to, in response to the smoothed difference exceeding thepredetermined value, generate a minor motion indication if the mode isset for animal detection, and suppress the minor motion indication ifthe mode is not set for animal detection. Some example computer programproducts also include computer readable code to receive the setting forthe mode though a wireless network, computer readable code to send theanimal-immune motion indication as a first message through the wirelessnetwork, and computer readable code to send the minor motion indicationas a second message through the wireless network. Any combination ofelements described in this paragraph may be used in various embodiments.

Another example method of detecting human motion within an infrareddetection area includes sensing infrared intensity within the infrareddetection area as received from at least two stacked non-overlappingdetection tiers, each having a plurality of non-overlapping monitoredvolumes, the plurality of non-overlapping monitored volumes of the atleast two detection tiers shifted from each other in a horizontaldirection by an offset, generating a major motion indication indicativeof a presence of a human in response to registering sufficient changesin the infrared intensity on vertically adjacent detection tiers of theat least two stacked detection tiers if the changes have a phaserelationship that corresponds to a critical phase angle, and ignoringchanges in the infrared intensity on vertically adjacent detection tiersof the at least two stacked detection tiers if the changes have a phaserelationship that does not correspond to the critical phase angle,wherein the critical phase angle is greater than 0 degrees. Some examplemethods also include ignoring a change in the infrared intensity thatoccurs in only one detection tier of the at least two stackednon-overlapping detection tiers. Some example methods also includegenerating a minor motion indication indicative of a presence of ananimal in response to a change in the infrared intensity that occurs inonly one detection tier of the at least two stacked non-overlappingdetection tiers. Some example methods also include obtaining a settingfor a mode for animal detection, and generating a minor motionindication indicative of a presence of an animal in response to a changein the infrared intensity that occurs in only one detection tier of theat least two stacked non-overlapping detection tiers if the mode is setfor animal detection, and suppressing the minor motion indication if themode is not set for animal detection. In some example methods thecritical phase angle is between 10 degrees and 80 degrees or between 100degrees and 170 degrees. In some example methods the critical phaseangle is 180 degrees times a percentage of a pitch of thenon-overlapping monitored volumes represented by the offset. Anycombination of elements described in this paragraph may be used invarious embodiments. Any example method may be implemented, at least inparty, using at least one machine readable medium comprising one or moreinstructions that in response to being executed on a computing devicecause the computing device to carry out a method according to thisparagraph.

Another infrared detector includes a substrate comprising a pyroelectricmaterial, a first row of detector elements positioned on the substrateand spaced a pitch distance apart, and a second row of detector elementspositioned on the substrate and spaced about the pitch distance apart,wherein the first row and the second row are substantiallynon-overlapping, and the second row of detector elements are positionedat a non-zero offset from the first row of detector elements in adirection parallel to the first row. In some example infrared detectorsthe first row of detector elements comprises at least two seriallycoupled detector elements, and the second row of detector elementscomprises at least two serially coupled detector elements. In someexample infrared detectors the non-zero offset is between 5% of thepitch distance and 95% of the pitch distance. In some example infrareddetectors the non-zero offset is about half of the pitch distance. Insome example infrared detectors the non-zero offset is a non-quadratureoffset. Some example infrared detectors also include a first outputcoupled to the first row of detector elements, and a second outputcoupled to the second row of detector elements. Some example infrareddetectors also include a package, wherein the substrate is mounted onthe package and positioned to allow external electromagnetic energy toaffect the substrate, at least one terminal accessible from outside ofthe package, and circuitry, mounted in the package and coupled to the atleast one terminal, the first row of detector elements, and the secondrow of detector elements, to detect a first pyroelectric effect on thefirst row of detector elements and a second pyroelectric effect on thesecond row of detector elements, and to provide information about thefirst pyroelectric effect and the second pyroelectric effect at the atleast one terminal. In some example infrared detectors the circuitrycomprises at least one analog-to-digital converter, and the informationabout the first pyroelectric effect and the second pyroelectric effectat the at least one terminal comprises digital data representing atleast one voltage waveform. In some example infrared detectors thecircuitry comprises a first transistor buffer coupled to the first rowof detector elements and a second transistor buffer coupled to thesecond row of detector elements, wherein the at least one terminalcomprises a first output terminal, a second output terminal, a powerterminal, and a ground terminal, and the information about the firstpyroelectric effect comprises a first analog voltage waveform at thefirst output terminal, and the information about the second pyroelectriceffect comprises a second analog voltage waveform at the second outputterminal. Any combination of elements described in this paragraph may beused in various embodiments.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. Thus, for example, reference to an elementdescribed as “a monitored volume” may refer to a single monitoredvolume, two monitored volumes, or any other number of monitored volumes.As used in this specification and the appended claims, the term “or” isgenerally employed in its sense including “and/or” unless the contentclearly dictates otherwise. As used herein, the term “coupled” includesdirect and indirect connections. Moreover, where first and seconddevices are coupled, intervening devices including active devices may belocated there between. Unless otherwise indicated, all numbersexpressing quantities of elements, percentages, and so forth used in thespecification and claims are to be understood as being modified in allinstances by the term “about.” Interpretation of the term “about” iscontext specific, but in the absence of other indications, shouldgenerally be interpreted as ±5% of the modified quantity, measurement,or distance. The recitation of numerical ranges by endpoints includesall numbers subsumed within that range (e.g. 1 to 5 includes 1, 2.78,3.33, and 5). Any element in a claim that does not explicitly state“means for” performing a specified function, or “step for” performing aspecified function, is not to be interpreted as a “means” or “step”clause as specified in 35 U.S.C. §112(f).

The description of the various embodiments provided above isillustrative in nature and is not intended to limit the invention, itsapplication, or uses. Thus, different variations beyond those describedherein are intended to be within the scope of the embodiments of thepresent invention. Such variations are not to be regarded as a departurefrom the intended scope of the present invention. As such, the breadthand scope of the present invention should not be limited by theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and equivalents thereof.

What is claimed is:
 1. A motion sensor comprising: an infrared detectorto provide first thermal information from a first row of monitoredvolumes having a pitch and second thermal information from a second rowof monitored volumes having the pitch and shifted in a directionparallel to the first row by an offset; and circuitry, coupled to theinfrared detector, to detect a phase relationship of waveforms extractedfrom the first thermal information and the second thermal information,and to generate an animal-immune motion indication if the phaserelationship corresponds to a critical phase angle; wherein the criticalphase angle is greater than 0 degrees, and is based on the offset andthe pitch.
 2. The motion sensor of claim 1, wherein the critical phaseangle is between 10 degrees and 80 degrees or between 100 degrees and170 degrees.
 3. The motion sensor of claim 1, wherein the critical phaseangle is 180 degrees times a percentage of the pitch represented by theoffset.
 4. The motion sensor of claim 1, wherein the first row ofmonitored volumes and the second row of monitored volumes aresubstantially non-overlapping.
 5. The motion sensor of claim 1, furthercomprising circuitry, coupled to the infrared detector, to detect asmoothed difference between the waveforms extracted from the firstthermal information and the second thermal information, and to generatea minor motion indication if the smoothed difference exceeds apredetermined value.
 6. The motion sensor of claim 1, wherein the firstthermal information includes thermal information from a first pluralityof aligned rows of monitored volumes that includes the first row ofmonitored volumes, and the second thermal information includes thermalinformation from a second plurality of aligned rows of monitored volumesthat includes the second row of monitored volumes; wherein the firstplurality of aligned rows of monitored volumes alternate with the secondplurality of aligned rows of monitored volumes.
 7. The motion sensor ofclaim 1, wherein the animal-immune motion indication comprises a visualindication or an audible indication.
 8. The motion sensor of claim 1,wherein the animal-immune motion indication comprises a radio frequencymessage.
 9. A method of detecting human motion within an infrareddetection area, comprising: sensing infrared intensity within theinfrared detection area as received from at least two stackednon-overlapping detection tiers, each having a plurality ofnon-overlapping monitored volumes, the plurality of non-overlappingmonitored volumes of the at least two detection tiers shifted from eachother in a horizontal direction by an offset; generating a major motionindication indicative of a presence of a human in response toregistering sufficient changes in the infrared intensity on verticallyadjacent detection tiers of the at least two stacked detection tiers ifthe changes have a phase relationship that corresponds to a criticalphase angle; and ignoring changes in the infrared intensity onvertically adjacent detection tiers of the at least two stackeddetection tiers if the changes have a phase relationship that does notcorrespond to the critical phase angle; wherein the critical phase angleis greater than 0 degrees.
 10. The method of claim 9, furthercomprising: ignoring a change in the infrared intensity that occurs inonly one detection tier of the at least two stacked non-overlappingdetection tiers.
 11. The method of claim 9, further comprising:generating a minor motion indication indicative of a presence of ananimal in response to a change in the infrared intensity that occurs inonly one detection tier of the at least two stacked non-overlappingdetection tiers.
 12. The method of claim 9, further comprising:obtaining a setting for a mode for animal detection; and generating aminor motion indication indicative of a presence of an animal inresponse to a change in the infrared intensity that occurs in only onedetection tier of the at least two stacked non-overlapping detectiontiers if the mode is set for animal detection, and suppressing the minormotion indication if the mode is not set for animal detection.
 13. Themethod of claim 9, wherein the critical phase angle is between 10degrees and 80 degrees or between 100 degrees and 170 degrees.
 14. Themethod of claim 9, wherein the critical phase angle is 180 degrees timesa percentage of a pitch of the non-overlapping monitored volumesrepresented by the offset.
 15. A computer program product for detectinghuman motion within an infrared detection area, the computer programproduct comprising: at least one non-transitory computer readablestorage medium having computer readable program code embodied therewith,the computer readable program code comprising: computer readable code tosense infrared intensity within the infrared detection area as receivedfrom at least two stacked non-overlapping detection tiers, each having aplurality of non-overlapping monitored volumes, the plurality ofnon-overlapping monitored volumes of the at least two detection tiersshifted from each other in a horizontal direction by an offset; computerreadable code to generate a major motion indication indicative of apresence of a human in response to registering sufficient changes in theinfrared intensity on vertically adjacent detection tiers of the atleast two stacked detection tiers if the changes have a phaserelationship that corresponds to a critical phase angle that is greaterthan 0 degrees; and computer readable code to ignore changes in theinfrared intensity on vertically adjacent detection tiers of the atleast two stacked detection tiers if the changes have a phaserelationship that does not correspond to the critical phase angle. 16.The computer program product of claim 15, further comprising computerreadable code to ignore a change in the infrared intensity that occursin only one detection tier of the at least two stacked non-overlappingdetection tiers.
 17. The computer program product of claim 15, furthercomprising computer readable code to generate a minor motion indicationindicative of a presence of an animal in response to a change in theinfrared intensity that occurs in only one detection tier of the atleast two stacked non-overlapping detection tiers.
 18. The computerprogram product of claim 15, further comprising: computer readable codeto obtain a setting for a mode for animal detection; and computerreadable code to generate a minor motion indication indicative of apresence of an animal in response to a change in the infrared intensitythat occurs in only one detection tier of the at least two stackednon-overlapping detection tiers if the mode is set for animal detection,and suppressing the minor motion indication if the mode is not set foranimal detection.
 19. The computer program product of claim 15, whereinthe critical phase angle is between 10 degrees and 80 degrees or between100 degrees and 170 degrees.
 20. The computer program product of claim15, wherein the critical phase angle is 180 degrees times a percentageof a pitch of the non-overlapping monitored volumes represented by theoffset.